Resources · 23

Prioritize vulnerabilities and verify remediation

Connect known exploitation, exposed assets, business impact and proof of a working fix.

· 9 min

Fictional cyber observatory with three trays separating advisories, inventory and remediation evidence, without people

What this guide helps achieve

  • Match alerts to assets
  • Rank actual urgency
  • Roll out safely
  • Verify and close

Quick check

  • Is the affected product and version actually deployed?
  • Is the asset reachable and business critical?
  • Is exploitation documented?
  • What protects the service before a patch?
  • Does a check confirm the problem is gone from the asset?

Step-by-step method

  1. 01

    Consolidate the inventory

    Map services, products, versions, environments, exposure and owners. A component advisory alone does not prove that a vulnerable instance is deployed.

    Deliverable: dated affected-asset list and uncertainties.

  2. 02

    Qualify the finding

    Compare the vendor advisory, CVE identifier, exploitation conditions and, where relevant, CISA’s catalog of known exploited vulnerabilities. Record when each source was checked.

    Deliverable: finding with primary references.

  3. 03

    Set a defensible priority

    Consider known exploitation, asset reachability, required privileges, data handled, service impact and available remediation. Assign an owner and context-specific deadline.

    Deliverable: reasoned priority decision.

  4. 04

    Prepare the change

    Map dependencies, change window, backup and rollback. If an update cannot be applied promptly, record the temporary control and its expiry.

    Deliverable: rollout plan and limited exception.

  5. 05

    Deploy and test

    Apply the vendor fix or mitigation using the approved process. Check the resulting version, business journey and integrations that may regress.

    Deliverable: deployment record and functional result.

  6. 06

    Verify closure

    Check the actual asset with a suitable method, find missed instances and revisit exceptions. Do not close a ticket because an update was merely scheduled.

    Deliverable: verification evidence and updated register.

Management indicators

IndicatorWhat it measuresFirst action
CoverageCritical assets with known versions and ownersComplete the inventory
DelayTime from qualification to verified fixRemove repeated bottlenecks
VerificationFixes retested on real assetsReopen closures without evidence
ExceptionsWaivers with control, owner and expiryClose expired exceptions

Common pitfalls

  • Ranking solely by a generic score without checking the asset
  • Assuming a KEV listing means the product exists in your estate
  • Deploying without testing service behaviour
  • Leaving compensating controls without a review date

Frequently asked questions

Must the highest-scored CVE always go first?

A score describes technical severity; known exploitation, exposure and local service impact guide your operational order.

What if no patch exists?

Follow vendor mitigations, reduce exposure where possible and document an owner, review date and residual risk.

When is the work closed?

After the version or mitigation has been verified on affected instances and critical functionality has been tested.

References: data, uses and limitations

Documentation reviewed on .

Vulnerability: three complementary viewsCVE · Identify. CVSS · Technical severity. EPSS · Probability. KEV · Known exploitation. Affected version and product. Score from 0.0 to 10.0. 30-day horizon. Official CISA catalogue. Local decision: exposure, impact, evidence and remediation checks.Vulnerability: three complementary viewsCVE · IdentifyAffected version and productCVSS · Technical severityScore from 0.0 to 10.0EPSS · Probability30-day horizonKEV · Known exploitationOfficial CISA catalogueLocal decision: exposure, impact, evidence and remediation checks
Vulnerability: three complementary views
References: data, uses and limitations
Source and purposeVerified data or benchmarkHow to use itLimitation to retain
FIRST · CVSS

Describe technical vulnerability severity using an explicit method and vector.

CVSS 4.0 scores run from 0.0 to 10.0. Base, Threat, Environmental and Supplemental metric groups serve different purposes. Retain the score version, vector and date. Compare it with the installed version, access paths and business consequences before ordering remediation.

Explore the method →

A high score is not evidence of exploitation; a low score does not mean a service has no risk.
FIRST · EPSS

Estimate exploitation probability for a published CVE.

The model looks ahead 30 days. Its score is a probability; its percentile ranks that score relative to other CVEs. Record the data date and distinguish probability from percentile. Add asset exposure and confirmed exploitation evidence.

Explore the method →

The model does not predict harm to your organisation. Low probability does not cancel a critical exposure.
CISA · Known Exploited Vulnerabilities

Identify vulnerabilities listed by CISA as known to be exploited.

The catalogue includes CVE, product, date added and required action. Its official repository also provides the data schema. Check applicability to your products and retain the access date. Review the requested action and vendor advisory before confirming remediation.

Explore the method →

Absence from the catalogue does not establish safety. Administrative deadlines in it are not automatically binding on every organisation.

CVSS, EPSS, KEV and VEX

Vulnerability prioritisation: four signals to connect to the asset

A vulnerability queue often mixes information answering different questions. CVSS describes technical severity, EPSS estimates a probability of observed exploitation, KEV records known exploitation and VEX carries a product applicability assertion. A local decision still needs the deployed version, access paths and consequences of exploitation.

These are documentary reference points. EPSS examples, situations and the VEX product are fictional; no current CVE score, real inventory or scan result is presented. This page calculates neither CVSS, organisational risk nor an automatic priority. Proposed evidence and decisions are a local editorial method.

Four distinct signals for a local decision
Four distinct signals for a local decision Four independent panels: CVSS describes severity; EPSS estimates observed exploitation within thirty days; KEV records known exploitation; VEX states declared applicability. Compare them with the deployed product and its context without adding them into one score. CVSS · Severity Metrics and vector Version and author EPSS · Probability Thirty-day horizon Separate date and rank KEV · Known exploitation Product and requested action Catalogue edition VEX · Applicability Issuer, product and time Status and justification Local decision: deployed asset, exposure, consequences, owner and evidence.

Four independent panels: CVSS describes severity; EPSS estimates observed exploitation within thirty days; KEV records known exploitation; VEX states declared applicability. Compare them with the deployed product and its context without adding them into one score.

Four questions and four kinds of information

Four questions and four kinds of information
SourceUseful questionWhat it cannot establish alone
CVSS 4.0What is the technical severity under the assessed metrics?The score proves neither exploitation nor consequences for your service.
EPSSWhat is the estimated probability of observing exploitation of this CVE in the next thirty days?It does not describe compromise of your instance, its controls or business loss.
CISA KEVIs the vulnerability listed as known to be exploited?Listing does not establish that the product exists in your estate; absence does not establish safety.
VEXWhat does an issuer assert about a vulnerability for identified products at a stated time?An assertion alone proves neither deployment of the relevant version nor issuer trustworthiness.

CVSS 4.0: preserve groups, vector and assessment author

A number from 0 to 10 loses meaning when its version, vector and assessed groups disappear. FIRST distinguishes CVSS-B, CVSS-BT, CVSS-BE and CVSS-BTE. Undefined Threat and Environmental metrics take default values rather than disappearing from the calculation.

CVSS 4.0: preserve groups, vector and assessment author
GroupRoleReading check
BaseIntrinsic vulnerability characteristics.A supplier’s CVSS-B is not your priority decision.
ThreatThreat characteristics that can change over time.Date the assessment and explain exploitation information used.
EnvironmentalCharacteristics specific to the consumer’s environment.State the controls and system importance considered rather than silently changing a score.
SupplementalAdditional context, such as Safety or Recovery.These metrics do not modify the final CVSS score; they may inform a separate local analysis.

EPSS: probability, percentile and missing data

FIRST describes a probability from 0 to 1, updated daily, over a thirty-day horizon. The percentile is a relative rank among currently scored vulnerabilities. Do not add probability and percentile or turn their pair into the probability of an attack on your organisation.

EPSS: probability, percentile and missing data
Fictional exampleProvided valuesCorrect reading
A probabilityProbability : 0.05 · Percentile : Unspecified0.05 means a 5% estimated probability of observed exploitation within the model horizon, rather than an estate compromise rate.
Probability and rankProbability : 0.02 · Percentile : 0.97In this fictional example 0.02 means 2%, while 0.97 places the score at the 97th percentile. The rank does not turn a 2% probability into 97%.
No received valueProbability : Unspecified · Percentile : UnspecifiedMissing data remains unknown; it is neither zero nor evidence of no exploitation. Record the failure or the date of the last available value.

Seven useful readings of the KEV schema

The official CISA repository schema describes the catalogue and its entries. The following selection helps retain consultation context rather than enumerate every field. Match each entry to the supplier advisory and actual asset.

Seven useful readings of the KEV schema
FieldsMeaningProposed check
catalogVersion / dateReleasedCatalogue version and publication time.Keep a reference to the consulted edition; distinguish publication time from your assessment time.
cveID / vendorProject / productIdentifier and product associated with the entry.Match name, version, distribution and embedded components before declaring an asset affected.
dateAddedDate the vulnerability entered the catalogue.Do not present it as the first exploitation date or CVE publication date.
requiredActionRequested action to address the vulnerability.Read the complete instruction and supplier references, then document local implementation.
dueDateCatalogue deadline for the requested action.Check the context and scope of the CISA instruction before adopting it as a local deadline.
knownRansomwareCampaignUseKnown indicates confirmed ransomware campaign use; Unknown means CISA lacks confirmation.Do not translate Unknown into never used or a definite false value.
cwesWeakness category codes associated with the entry.Use categories to group causes; they do not replace the CVE identifier or affected version.

Six fictional situations: what is missing before a decision?

High severity, product not located

An advisory reports high severity; the inventory cannot locate that version in the estate.

Confirm presence and version with the owner, including embedded dependencies.

Retain applicability unknown. Absence from an incomplete inventory does not justify closure.

Known exploitation, exposed instance

The vulnerability is listed as known to be exploited and an owner confirms an affected internet-accessible instance.

Review supplier actions and arrange exposure reduction and remediation suited to the service.

Name the owner, interim control and expected verification evidence; a severity score alone supplies none of this traceability.

Low probability, essential service

The fictional EPSS probability is low, but the affected instance supports an essential service.

Assess consequences and access paths before agreeing a change window.

Do not treat a low score as insurance; that instance’s controls are not contextual inputs to EPSS.

VEX for another version

The supplier declares version 2.4.0 not affected; the asset still runs 2.3.0.

Seek an assertion applicable to the installed version and verify its provenance.

Do not extend a conclusion across versions. A VEX document deploys no update.

Temporary control becomes permanent

A temporary rule reduces access; its review date has passed.

Check that it still protects the relevant path, then decide whether to maintain it or apply the fix.

Keep the owner, limits and a new review date. A perimeter control is not automatically an OpenVEX built-in product mitigation.

Patch announced, deployment unverified

A fixed release is available, but the ticket contains only a download link.

Check the version actually deployed, remaining instances and critical functionality.

Close on implementation and verification evidence, rather than the supplier’s availability of a patch.

Eight records for a traceable remediation decision

  • Product, version or build, environment and asset owner.
  • Vulnerability identifier, supplier advisory and relevant exploitation conditions.
  • CVSS version, vector, metric-group nomenclature and assessment author.
  • EPSS date, probability and percentile in separate fields, or an explicit missing value.
  • Dated KEV status, requested action and consulted catalogue edition.
  • Applicable VEX assertion: issuer, product, version, time and any justification.
  • Reasoned local decision, interim control, owner and review date.
  • Deployment or mitigation evidence, verification result and remaining limits.

Read VEX statuses and applicability conditions →

Primary sources and scope

Sources checked on

Build signatures and provenance

Verify patch origin and then its application

A fixed version needs connecting to the received package and updated instance. Provenance verification helps establish expected origin; remediation confirmation still requires checking the active version and relevant behaviour.

  • Keep the accepted patch digest and signature/provenance verification results.
  • Match that package to the version actually deployed on each targeted instance.
  • Do not close on authenticity alone: document remediation checks, regressions and remaining limits.

Read the pre-deployment provenance reference →

Sources checked on · SLSA 1.2 · Build: Verifying artifacts · SLSA 1.2 · Build: Provenance · SLSA 1.2 · Build: Track Basics · in-toto · Statement v1 · Sigstore · Verifying Signatures

Explore the CISA KEV catalogue

KEV is CISA’s catalogue of vulnerabilities known to be exploited. This explorer contains a complete dated snapshot, not a live feed. A CVE or product-name match is a lead to compare with the exact deployed product and version; it does not prove that a visitor’s system is vulnerable or compromised.

Entry names, products, descriptions, required actions and links retain CISA’s language and values. Explanations are editorial. Entries may be added or corrected after this snapshot; consult the official source before an operational decision.

Entries
1769
Distinct vendor/project labels
291
Catalogue release date

Counters describe this snapshot only. They do not measure attack counts, vulnerability prevalence or an organisation’s risk. Distinct vendorProject labels are counted exactly as published, without merging aliases or treating them as distinct companies.

Unknown means CISA lacks confirmation of use in a ransomware campaign; it does not mean no exploitation. forensicTriage Yes/No is a separate field described by the schema with a reference to BOD 26-04. An absent field stays unreported. Neither No nor Unknown demonstrates that your asset has not been compromised.

dueDate is the deadline published in the CISA entry for the stated action. It is not a universal SLA, a patch release date or evidence that a patch was installed. The forensicTriage field alone cannot determine your obligations or define an investigation plan.

Six readings that prevent a misleading priority

Six readings that prevent a misleading priority
Published fieldUseful readingConclusion to avoid
cveIDJoin sources discussing the same vulnerability.The identifier year does not date KEV inclusion.
vendorProject · productFind the vendor advisory and local inventory.A product name does not replace affected versions and configurations.
dateAddedDate the entry’s inclusion in this catalogue.Do not call it discovery or first-exploitation date.
dueDate · requiredActionRead the published action and deadline together.Do not turn the date into a universal obligation or proof of remediation.
knownRansomwareCampaignUsePreserve Known, Unknown or an absent field.Unknown is not No and does not remove the known exploitation signal underlying KEV.
forensicTriage · cwesSeparate CISA’s indicator from published weakness classes.A CWE is not a specific product or score; No is not a certificate that no incident occurred.

Catalogue additions by year

Catalogue additions by yearEach bar counts entries retained in this snapshot by the year of dateAdded. It is not a discovery year or an exploitation frequency. The first year starts at this snapshot’s earliest entry and the release year is incomplete; these totals are not an annual attack trend.311202155520221872023186202424520252852026
Each bar counts entries retained in this snapshot by the year of dateAdded. It is not a discovery year or an exploitation frequency. The first year starts at this snapshot’s earliest entry and the release year is incomplete; these totals are not an annual attack trend.
Catalogue additions by year · dateAdded
Year addedEntries
2021311
2022555
2023187
2024186
2025245
2026285

Results : 311 / 1769 · Page 9 / 13

Explore the CISA KEV catalogue · 2026.11.06
CVEVendor or project · productDate added / Entry due dateUse in ransomware campaigns / forensicTriage
CVE-2020-8657

CWE-798

EyesOfNetwork

EyesOfNetwork

Entry and action published by CISA

EyesOfNetwork Use of Hard-Coded Credentials Vulnerability

EyesOfNetwork contains a use of hard-coded credentials vulnerability, as it uses the same API key by default. Exploitation allows an attacker to calculate or guess the admin access token.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2020-8657

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2020-9818

CWE-787

Apple

iOS, iPadOS, and watchOS

Entry and action published by CISA

Apple iOS, iPadOS, and watchOS Out-of-Bounds Write Vulnerability

Apple iOS, iPadOS, and watchOS Mail contains an out-of-bounds write vulnerability which may allow memory modification or application termination when processing a maliciously crafted mail message.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2020-9818

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2020-9819

CWE-787

Apple

iOS, iPadOS, and watchOS

Entry and action published by CISA

Apple iOS, iPadOS, and watchOS Memory Corruption Vulnerability

Apple iOS, iPadOS, and watchOS Mail contains a memory corruption vulnerability that may allow heap corruption when processing a maliciously crafted mail message.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2020-9819

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2020-9859

CWE-415

Apple

Multiple Products

Entry and action published by CISA

Apple Multiple Products Code Execution Vulnerability

Apple iOS, iPadOS, macOS, watchOS, and tvOS contain an unspecified vulnerability that may allow an application to execute code with kernel privileges.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2020-9859

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1497

CWE-78

Cisco

HyperFlex HX

Entry and action published by CISA

Cisco HyperFlex HX Installer Virtual Machine Command Injection Vulnerability

Cisco HyperFlex HX Installer Virtual Machine contains an insufficient input validation vulnerability which could allow an attacker to execute commands on an affected device as the root user.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1497

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1498

CWE-78

Cisco

HyperFlex HX

Entry and action published by CISA

Cisco HyperFlex HX Data Platform Command Injection Vulnerability

Cisco HyperFlex HX Installer Virtual Machine contains an insufficient input validation vulnerability which could allow an attacker to execute commands on an affected device as the tomcat8 user.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1498

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1647

CWE-122, CWE-1285

Microsoft

Defender

Entry and action published by CISA

Microsoft Defender Remote Code Execution Vulnerability

Microsoft Defender contains an unspecified vulnerability that allows for remote code execution.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1647

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1675

CWE-285

Microsoft

Windows

Entry and action published by CISA

Microsoft Windows Print Spooler Remote Code Execution Vulnerability

Microsoft Windows Print Spooler contains an unspecified vulnerability that allows for remote code execution.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1675

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-1732

CWE-787

Microsoft

Win32k

Entry and action published by CISA

Microsoft Win32k Privilege Escalation Vulnerability

Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1732

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-1782

CWE-362, CWE-667

Apple

Multiple Products

Entry and action published by CISA

Apple Multiple Products Race Condition Vulnerability

Apple iOS, iPadOs, macOS, watchOS, and tvOS contain a race condition vulnerability that may allow a malicious application to elevate privileges.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1782

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1870

CWE-1173

Apple

iOS, iPadOS, and macOS

Entry and action published by CISA

Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability

Apple iOS, iPadOS, and macOS WebKit contain an unspecified logic vulnerability that allows a remote attacker to execute code. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1870

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1871

CWE-1173

Apple

iOS, iPadOS, and macOS

Entry and action published by CISA

Apple iOS, iPadOS, and macOS WebKit Remote Code Execution Vulnerability

Apple iOS, iPadOS, and macOS WebKit contain an unspecified logic vulnerability that allows a remote attacker to execute code. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1871

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1879

CWE-79

Apple

iOS, iPadOS, and watchOS

Entry and action published by CISA

Apple iOS, iPadOS, and watchOS WebKit Cross-Site Scripting (XSS) Vulnerability

Apple iOS, iPadOS, and watchOS WebKit contain an unspecified vulnerability that allows for universal cross-site scripting (XSS) when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1879

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1905

CWE-416

Qualcomm

Multiple Chipsets

Entry and action published by CISA

Qualcomm Multiple Chipsets Use-After-Free Vulnerability

Multiple Qualcomm Chipsets contain a use after free vulnerability due to improper handling of memory mapping of multiple processes simultaneously.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1905

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-1906

CWE-390

Qualcomm

Multiple Chipsets

Entry and action published by CISA

Qualcomm Multiple Chipsets Detection of Error Condition Without Action Vulnerability

Multiple Qualcomm chipsets contain a detection of error condition without action vulnerability when improper handling of address deregistration on failure can lead to new GPU address allocation failure.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-1906

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-20016

CWE-89

SonicWall

SSLVPN SMA100

Entry and action published by CISA

SonicWall SSLVPN SMA100 SQL Injection Vulnerability

SonicWall SSLVPN SMA100 contains a SQL injection vulnerability that allows remote exploitation for credential access by an unauthenticated attacker.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-20016

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-20021

CWE-306

SonicWall

SonicWall Email Security

Entry and action published by CISA

SonicWall Email Security Improper Privilege Management Vulnerability

SonicWall Email Security contains an improper privilege management vulnerability that allows an attacker to create an administrative account by sending a crafted HTTP request to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20022 and CVE-2021-20023 to achieve privilege escalation.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-20021

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-20022

CWE-434

SonicWall

SonicWall Email Security

Entry and action published by CISA

SonicWall Email Security Unrestricted Upload of File Vulnerability

SonicWall Email Security contains an unrestricted upload of file with dangerous type vulnerability that allows a post-authenticated attacker to upload a file to the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20023 to achieve privilege escalation.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-20022

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-20023

CWE-22

SonicWall

SonicWall Email Security

Entry and action published by CISA

SonicWall Email Security Path Traversal Vulnerability

SonicWall Email Security contains a path traversal vulnerability that allows a post-authenticated attacker to read files on the remote host. This vulnerability has known usage in a SonicWall Email Security exploit chain along with CVE-2021-20021 and CVE-2021-20022 to achieve privilege escalation.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-20023

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Known
forensicTriage
No
CVE-2021-20090

CWE-22

Arcadyan

Buffalo Firmware

Entry and action published by CISA

Arcadyan Buffalo Firmware Path Traversal Vulnerability

Arcadyan Buffalo firmware contains a path traversal vulnerability that could allow unauthenticated, remote attackers to bypass authentication and access sensitive information. This vulnerability affects multiple routers across several different vendors.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-20090

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-21017

CWE-122

Adobe

Acrobat and Reader

Entry and action published by CISA

Adobe Acrobat and Reader Heap-based Buffer Overflow Vulnerability

Acrobat Acrobat and Reader contain a heap-based buffer overflow vulnerability that could allow an unauthenticated attacker to achieve code execution in the context of the current user.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-21017

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-21148

CWE-122

Google

Chromium V8

Entry and action published by CISA

Google Chromium V8 Heap Buffer Overflow Vulnerability

Google Chromium V8 Engine contains a heap buffer overflow vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-21148

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-21166

CWE-122, CWE-362

Google

Chromium

Entry and action published by CISA

Google Chromium Race Condition Vulnerability

Google Chromium contains a race condition vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-21166

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-21193

CWE-416

Google

Chromium Blink

Entry and action published by CISA

Google Chromium Blink Use-After-Free Vulnerability

Google Chromium Blink contains a use-after-free vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-21193

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No
CVE-2021-21206

CWE-416

Google

Chromium Blink

Entry and action published by CISA

Google Chromium Blink Use-After-Free Vulnerability

Google Chromium Blink contains a use-after-free vulnerability that allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

requiredAction
Apply updates per vendor instructions.
notes
https://nvd.nist.gov/vuln/detail/CVE-2021-21206

nvd.nist.gov ↗

dateAdded
dueDate
knownRansomwareCampaignUse
Unknown
forensicTriage
No

An old identifier can enter the catalogue recently

CVE-2015-5477, associated with ISC BIND in this snapshot, has identifier year 2015 and dateAdded 8 October 2026. These dates answer different questions. The entry calls for following vendor instructions; it does not establish your BIND version, exposure or installation of a fix.

From a public signal to a documented decision

  1. Qualify the match

    Keep the CVE, source and date, then establish product, version, embedded component and exposure. An SBOM may locate a component without proving its runtime condition.

  2. Read the action at its source

    Open the vendor advisory and updates. Separate updating, mitigation, discontinuing a product and searching for compromise evidence; a patch does not replace these other decisions.

  3. Document the change

    Assign an owner, prepare rollback and verify dependencies. A mitigation remains a scoped measure with an explicit validity period.

  4. Verify the resulting state

    Retain an observed version, checked configuration and service test. Closing a task needs evidence concerning the actual asset, beyond a console status.

Source release : · Documentary review :

CISA KEV data reused under CC0 1.0. Reuse implies no CISA affiliation or endorsement and grants no right to use the CISA logo or DHS seal.

Reference details · CISA KEV

How we publish this official snapshot

The copy is identified by its catalogue version, dateReleased, official mirror commit and source-file digest. CISA publication, GitHub synchronisation and our review are distinct events. Aggregates are computed from the retained entries; no visitor inventory collection or vulnerability scan takes place.

catalogVersion
2026.11.06
dateReleased
GitHub commit
e5b3a9b25050a8da26c96266c5bfe438ee0bdebc ·
SHA-256
47e0406b2be5a40420eff66f3d90e83eb8883dae6ff4d08e1b2a942c366f6cc2

Counters describe this snapshot only. They do not measure attack counts, vulnerability prevalence or an organisation’s risk. Distinct vendorProject labels are counted exactly as published, without merging aliases or treating them as distinct companies.

Explore the catalogue and method →

Source release : · Documentary review :

CISA KEV data reused under CC0 1.0. Reuse implies no CISA affiliation or endorsement and grants no right to use the CISA logo or DHS seal.

Official references

References consulted: . The method and worksheet propose checks to adapt to your context; they do not constitute certification.