ClamAV: prepare service continuity

At a glance

ClamAV: denial of service. This 2026-07-05 case examines 2 version entries and 8 CVEs, documented releases and checks suited to detection tools, using CERTFR-2026-AVI-0824.

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In this article

Retrospective for 2026-07-05, compiled on 27 October 2026. The date identifies the day being analysed; source publication and revision dates are recorded below.

What this advisory changes in your environment

The starting point is CERTFR-2026-AVI-0824, published on 2026-07-02. Its scope includes ClamAV. Reported consequences are impact requiring vendor clarification, denial of service. These statements apply to the advisory’s scope; they do not assign every consequence to every product or CVE.

This case focuses on ClamAV. Locate that edition in live installations, deployment images and actual dependencies, rather than treating every product from ClamAV as equivalent.

Products and versions to examine

Reference
CERTFR-2026-AVI-0824
Source first published
2026-07-02
Latest source revision available for this day
2026-07-02
Named components
ClamAV
CVE identifiers
CVE-2026-20216, CVE-2026-20243, CVE-2026-20215, CVE-2026-20213, CVE-2026-20214, CVE-2026-20217, CVE-2026-20244, CVE-2026-41676
ComponentPublished condition
ClamAV< 1.4.5
ClamAV1.5.x : < 1.5.3

For ClamAV, the published condition is “< 1.4.5”. Compare the version actually loaded with that condition within its own release branch. A fix installed on another edition of ClamAV does not close this case.

Mechanism and prerequisites

Denial of service may interrupt a component without establishing data theft. Assess business dependencies, recovery capabilities and resource limits; test failover without generating hostile production traffic.

The primary record CVE-2026-20216, published by cisco, covers Cisco Secure Endpoint. The retained revision is dated 2026-07-01. Its scope is presented separately from the integrations and product groupings in CERTFR-2026-AVI-0824.

The published metric for CVE-2026-20216 is CVSS 3.1, 7.5/10. The vector below describes technical prerequisites; it does not measure attack frequency or the likelihood that your deployment is compromised.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector
network
Prior privileges
none
User interaction
none
Complexity
low
Weakness
CWE-770

Choose the appropriate intervention

  1. Locate ClamAV instances, running releases and service owners. Record condition < 1.4.5 in the ticket alongside reference CERTFR-2026-AVI-0824.
  2. Compare the installed branch with the vendor’s ClamAV release notes. Prepare the package for that branch and a dependent-service test, retaining the pre-change state.
  3. After changing ClamAV, capture the loaded version again and verify the workflow below. Any exception needs an owner, an exposure-reduction measure and an expiry date.

Verify the fix in a real workflow

Validation scenario to adapt for ClamAV: In a test instance of ClamAV, submit a known synthetic event through the normal collection channel. Confirm receipt, timestamp and processing; check that updating the collector has not left another vulnerable agent or module installed. This is a proposed defensive check, not a claim that testing was performed against third-party systems.

Limit of case CERTFR-2026-AVI-0824: this analysis replaces neither vendor prerequisites nor investigation of your logs. Only documented versions are reproduced; no attack date or victim is invented.

Questions specific to this case

Which condition should be checked for ClamAV?

Advisory CERTFR-2026-AVI-0824 states: ClamAV — < 1.4.5. Check the edition and running release; do not extend the published boundary to branches absent from the advisory.

Which prerequisites does record CVE-2026-20216 specify?

For CVE-2026-20216, the published vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Verify those conditions on Cisco Secure Endpoint before applying them to an integration named in CERTFR-2026-AVI-0824.

Sources and related reading

Practical guide : Make security event logs ready for detection

Explore the decision addressed in this case

Complete source advisory inventory

The article table may be an extract. These lists contain every affected-system entry and CVE in the specified advisory revision. They are not an inventory of your assets and do not map every CVE to every product.

Official source · CERTFR-2026-AVI-0824
Advisory revision : · Checked on :

Affected systems · 2

Original French wording is retained to avoid ambiguous translations of version conditions.

  1. ClamAV versions antérieures à 1.4.5
  2. ClamAV versions 1.5.x antérieures à 1.5.3
CVE identifiers · 8