CVE-2026-53599

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.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 43% of CVEs (scores of 2026-10-25)

CWE

CWE-434

Published

2026-07-31

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

References

• https://github.com/redaxo/core/commit/462e36896bb65d292ba22d711044c23c9cfb0340
• https://github.com/redaxo/core/pull/6538
• https://github.com/redaxo/core/releases/tag/5.21.1
• https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25
• https://github.com/redaxo/core/security/advisories/GHSA-98pp-vccm-qm25

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