CVE-2026-81920: Concrete CMS below 9.5.3 was vulnerable to Cross-Site Request Forgery in the dashboard SEO Excluded
Source GCVE Database
Not known to be exploited · CVSS 4.3 Medium · fixed in 9.5.3 : update affected systems when convenient.
Data as of 31 Oct 2026, 20:20 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 9.5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 15 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.
What to do
AI-suggested
A fix is available in Concrete CMS version 9.5.3 and later. Users should upgrade to version 9.5.3 or above to remediate this vulnerability. Until then, restricting access to the SEO Excluded Words page and ensuring users do not visit untrusted pages while authenticated can reduce risk.
Description
Concrete CMS versions below 9.5.3 contain a Cross-Site Request Forgery (CSRF) vulnerability in the dashboard SEO Excluded Words page. The reset() controller action that clears the reserved-word list does not validate the anti-CSRF token and does not restrict the request to POST, allowing an attacker to revert the reserved-word list to default silently. This could alter future URL slug generation, undoing the site's SEO slug policy. The vulnerability has a low severity score of 2.3 according to the Concrete CMS security team.