How to Fix CVE-2026-3242: Concrete CMS (Bundle Sibling)
By Sai Kiran Pandrala. Last verified: 2026-05-25.
CVE-2026-3242 is a sibling vulnerability in the same vendor advisory as CVE-2026-2994. Apply the same patched build and you close both. The technical detail below is what differs.
| Severity | 4.8 (Medium) |
|---|---|
| Actively exploited? | No public listing in CISA KEV |
| Affected | Concrete CMS 5 to <9.4.8 |
| Fixed in | Same patched build as CVE-2026-2994 |
| Type (CWE) | CWE-79 Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') |
What's different about CVE-2026-3242?
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 to fix CVE-2026-3242
Apply the patched build per the primary write-up: How to Fix CVE-2026-2994. All commands, verification steps, and rollback notes for Concrete CMS are listed there.
Frequently asked questions
Does the CVE-2026-2994 patch close CVE-2026-3242?
Yes. Both CVEs are addressed by the same vendor patch. Applying the patched build closes the full bundle.
Is CVE-2026-3242 listed in CISA KEV?
No public KEV listing at the time of this writing.
Where is the official advisory?
See https://github.com/concretecms/concretecms/pull/12826
References
- Official vendor advisory: https://github.com/concretecms/concretecms/pull/12826
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-3242
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary: How to Fix CVE-2026-2994
*Written by Sai Kiran Pandrala. Part of the Concrete CMS bundle. Full procedure at how-to-fix-cve-2026-2994.*