CVE-2026-53599 HIGH

CVE-2026-53599: Redaxo has a Mediapool isAllowedExtension bypass via multi-segment filename that leads to authenticated RCE on Apache mod_php multi-extension handlers

Vendor Redaxo
Product core
Weakness CWE-434 · Unrestricted file upload
Published July 31, 2026
Last update July 31, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 31, 2026 CVE published
July 31, 2026 Record updated

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04Related CVE

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