Retrospective for 2026-07-08, 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-0847, published on 2026-07-08. Its scope includes Joomla!. Reported consequences are cross-site scripting (XSS), data integrity compromise, security control bypass, loss of confidentiality. These statements apply to the advisory’s scope; they do not assign every consequence to every product or CVE.
This case focuses on Joomla!. Locate that edition in live installations, deployment images and actual dependencies, rather than treating every product from Joomla! as equivalent.
Products and versions to examine
- Reference
- CERTFR-2026-AVI-0847
- Source first published
- 2026-07-08
- Latest source revision available for this day
- 2026-07-08
- Named components
- Joomla!
- CVE identifiers
- CVE-2026-48957, CVE-2026-48950, CVE-2026-48953, CVE-2026-48948, CVE-2026-48949, CVE-2026-48956, CVE-2026-48958, CVE-2026-48951, CVE-2026-48954, CVE-2026-48955, CVE-2026-48947, CVE-2026-48952
| Component | Published condition |
|---|---|
| Joomla! | 6.x : < 6.1.2 |
| Joomla! | < 5.4.7 |
For Joomla!, the published condition is “6.x : < 6.1.2”. Compare the version actually loaded with that condition within its own release branch. A fix installed on another edition of Joomla! does not close this case.
Mechanism and prerequisites
XSS abuses the trust a browser places in a page. Inspect untrusted content rendering, administrative sessions and output controls; input filtering alone does not establish that executable scripts are impossible.
The primary record CVE-2026-48957, published by Joomla, covers Joomla! CMS. The retained revision is dated 2026-07-08. Its scope is presented separately from the integrations and product groupings in CERTFR-2026-AVI-0847.
The published metric for CVE-2026-48957 is CVSS 4.0, 6.4/10. The vector below describes technical prerequisites; it does not measure attack frequency or the likelihood that your deployment is compromised.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:H
- Attack vector
- network
- Prior privileges
- high
- User interaction
- none
- Complexity
- low
- Additional attack requirements
- none
- Weakness
- CWE-284
Choose the appropriate intervention
- Locate Joomla! instances, running releases and service owners. Record condition 6.x : < 6.1.2 in the ticket alongside reference CERTFR-2026-AVI-0847.
- Compare the installed branch with the vendor’s Joomla! release notes. Prepare the package for that branch and a dependent-service test, retaining the pre-change state.
- After changing Joomla!, 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 Joomla!: On a test copy of Joomla!, compare ordinary and administrative accounts on the same workflow. Check creation, reading and modification of a synthetic object, then inspect submitted-content rendering without exposing real data. This is a proposed defensive check, not a claim that testing was performed against third-party systems.
Limit of case CERTFR-2026-AVI-0847: 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 Joomla!?
Advisory CERTFR-2026-AVI-0847 states: Joomla! — 6.x : < 6.1.2. Check the edition and running release; do not extend the published boundary to branches absent from the advisory.
Which prerequisites does record CVE-2026-48957 specify?
For CVE-2026-48957, the published vector is CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:H. Verify those conditions on Joomla! CMS before applying them to an integration named in CERTFR-2026-AVI-0847.
Sources and related reading
- CERT-FR · CERTFR-2026-AVI-0847
- Vendor and remediation · developer.joomla.org
- Vendor and remediation · developer.joomla.org
- Vendor and remediation · developer.joomla.org
- Vendor and remediation · developer.joomla.org
- CVE-2026-48957 · CNA
Practical guide : Software inventory: prepare for end of support
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-0847
Advisory revision : · Checked on :
Affected systems · 2
Original French wording is retained to avoid ambiguous translations of version conditions.
- Joomla! versions 6.x antérieures à 6.1.2
- Joomla! versions antérieures à 5.4.7