CVE-2026-56662

GetSimple CMS is a content management system (CMS), and GetSimple CMS CE is the community edition of that CMS. Prior to version 1.5, the UpdateCE update form contained no anti-CSRF token, and the POST handler performed no token or request-origin verification. A remote attacker can host a page that auto-submits a forged POST to the update endpoint; when an authenticated administrator visits it, the server performs an attacker-directed download-and-deploy operation in the administrator's session — with no further interaction. Because the deployed content is executed (see the related ZIP-extraction advisory), this yields remote code execution. The url field is additionally written into the form unescaped, providing a secondary HTML-injection sink via a malicious upgrade.json. This issue has been patched in version 1.5.

• https://github.com/GetSimpleCMS-CE/GetSimpleCMS-CE/security/advisories/GHSA-2rxv-4g4m-573w
• https://github.com/GetSimpleCMS-CE/GetSimpleCMS-CE/security/advisories/GHSA-2rxv-4g4m-573w