CVE-2026-53599

HIGH7.5

Redaxo has a Mediapool isAllowedExtension bypass via multi-segment filename that leads to authenticated RCE on Apache mod_php multi-extension handlers

Published Jul 31, 2026

Modified 3 weeks ago

Details

REDAXO is a PHP-based content management system. From 5.18.2 until 5.21.1, rex_mediapool::isAllowedExtension in redaxo/src/addons/mediapool/lib/mediapool.php lets an authenticated backend user with media[upload] permission upload a JPEG/PHP polyglot named shell.php.any.jpg, which web servers with multi-extension PHP handlers can execute as the web-server user. This issue is fixed in version 5.21.1.

References

WEB

https://github.com/redaxo/core/commit/462e36896bb65d292ba22d711044c23c9cfb0340

WEB

https://github.com/redaxo/core/pull/6538

WEB

https://github.com/redaxo/core/releases/tag/5.21.1

WEB

https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-53599

CVSS Analysis