CVE-2026-81901 Concrete CMS - Stored XSS

Concrete CMS 9.2.0 through 9.5.2 contains a stored XSS caused by missing authorization checks on page properties, templates, and types in the REST API page update endpoint, letting users with content-editing rights persist JavaScript executing in visitors' browsers, exploit requires user with content-editing rights.

CVSS base score 8.7 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.38% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Stored XSS
Impact
Stored XSS
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Published
14 September 2026
Updated
15 October 2026
Weakness
CWE-862

Vendor fix

Update to a version later than 9.5.2 or the latest available version.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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