Moderate severityNVD Advisory· Published Mar 4, 2026· Updated Mar 4, 2026

Concrete CMS below 9.4.8 is vulnerable to Stored XSS in the Switch Language block

CVE-2026-3242

Description

In Concrete CMS below version 9.4.8, a rogue administrator can add stored XSS via the Switch Language block. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks M3dium for reporting.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
concrete5/concrete5Packagist	< 9.4.8	9.4.8

Affected products

ghsa-coords
pkg:composer/concrete5/concrete5
Range: < 9.4.8
Concrete CMS/Concrete CMSv5
Range: 5

Patches

Vulnerability mechanics

References

github.com/advisories/GHSA-w9qg-chfh-g3q9ghsaADVISORY
nvd.nist.gov/vuln/detail/CVE-2026-3242ghsaADVISORY
documentation.concretecms.org/9-x/developers/introduction/version-history/948-release-notesghsaWEB
github.com/concretecms/concretecms/pull/12826ghsaWEB

News mentions

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cvss	0.260
epss	0.000
exploit	0.000
kev	0.000
patch	-0.070
ransomware	0.000