CVE-2026-53599CWE-434unrestricted-file-upload

CVE-2026-53599

High · published August 1, 2026

CVSS v3.1

7.5

EPSS

Percentile

42.5

In the wild

Unconfirmed

What it is

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.

The record

Technical detail

CVSS v3.1: 7.5 · HIGH
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0: Not supplied
EPSS: 0.00508 · 42.5th percentile
Weakness: CWE-434 · Unrestricted Upload of File with Dangerous Type
Published: 2026-08-01T00:16Z

References (5)

https://github.com/redaxo/core/commit/462e36896bb65d292ba22d711044c23c9cfb0340 · [email protected]https://github.com/redaxo/core/pull/6538 · [email protected]https://github.com/redaxo/core/releases/tag/5.21.1 · [email protected]https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25 · [email protected]https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25 · 134c704f-9b21-4f2e-91b3-4a467353bcc0

EPSS history

Timeline

31 JUL 19:43Z
Redaxo has a Mediapool isAllowedExtension bypass via multi-segment filename that leads to authenticated RCE on Apache mod_php multi-extension handlers
cvelistv5