CVE-2026-88418 CMSimple - Stored XSS & Remote Code Execution

CMSimple 5.24 contains a stored XSS and remote code execution caused by disabled CSRF protection and unsanitized scripting markers in admin content saving, letting unauthenticated attackers execute arbitrary PHP code via a logged-in admin's browser.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.25% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Stored XSS
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Published
22 September 2026
Updated
15 October 2026
Weakness
CWE-352

Vendor fix

Enable CSRF protection by default and sanitize scripting markers in admin content saving; update to the latest CMSimple 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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