CVE-2026-88418
HighCVSS 8.8Exploitation Probability (EPSS)
Low risk15th percentile - higher than 15% of all known CVEs
Summary
CMSimple 5.24 ships with CSRF protection disabled by default, which turns csrfProtection() into a no-op on every state-changing admin request, and it does not send the csrf_token hidden field in admin forms. Because administrator authentication is cookie-only and no CSRF token is enforced, an unauthenticated attacker can induce a logged-in administrator's browser to issue a forged content-save request with a text payload containing a scripting marker. The marker is stored verbatim into content/content.php; on every subsequent page view evaluate_cmsimple_scripting() (functions.php) executes the marker body with PHP eval() — for all visitors, including unauthenticated ones. This yields persistent remote code execution on the web server.
Risk Assessment
This results in persistent remote code execution on the web server for all visitors, including unauthenticated ones, potentially leading to full server compromise.
Recommendation
Immediately update CMSimple to a patched version, and in the meantime enable CSRF protection and enforce CSRF tokens in admin forms.
Other vulnerabilities in CMSimple
See all- CVE-2026-78834High
A code execution vulnerability exists in CMSimple 5.22 in the CoAuthors plugin. An authenticated low-privileged user who can modify page content and provide controlled imported content can trigger server-side execution by referencing crafted external or uploaded text content through the affected content import feature.
- CVE-2024-58280High
CMSimple 5.15 contains a remote command execution vulnerability that allows authenticated attackers to modify file extensions and upload malicious PHP files. Attackers can append ',php' to Extensions_userfiles and upload a shell script to the media directory to execute arbitrary code on the server.
Original NVD description (English source)
CMSimple 5.24 ships with CSRF protection disabled by default, which turns csrfProtection() into a no-op on every state-changing admin request, and it does not send the csrf_token hidden field in admin forms. Because administrator authentication is cookie-only and no CSRF token is enforced, an unauthenticated attacker can induce a logged-in administrator's browser to issue a forged content-save request with a text payload containing a scripting marker. The marker is stored verbatim into content/content.php; on every subsequent page view evaluate_cmsimple_scripting() (functions.php) executes the marker body with PHP eval() — for all visitors, including unauthenticated ones. This yields persistent remote code execution on the web server.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS