🛡️ CVE-2026-3242 — concrete-cms

🟡 CVSS 4.8 — Medium ⚠️ Exploit Public CWE-79 NVD
4.8
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs administrative privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-3242 is classified as CWE-79: Cross-site Scripting (XSS). User-supplied data is written into a page without escaping, so attacker script runs in the browser of anyone who views it.

Affected software

CVE-2026-3242 is recorded against 2 packages.

  • concrete-cms (fixed in 9.4.8)
  • concrete5/concrete5 (fixed in 9.4.8)

Timeline and source

Published on 4 March 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

documentation.concretecms.org
github.com

Details

Severity MEDIUM
CVSS Score 4.8
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
CWE CWE-79
Public Exploit ⚠️ Yes
Source NVD
Published 2026-03-04
Updated 2026-08-12
Modified 2026-06-17

Affected Packages

Software From version Fixed in
concrete-cms — 9.4.8
concrete5/concrete5 — 9.4.8

Similar Threats

Exploit Protection

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CVE-2026-3242 carries CVSS 4.8 Medium rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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