CVE-2026-53599

EUVD-2026-51626
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
GitHub_MCNA
7.5 HIGH
NETWORK
HIGH
LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 43.34%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
redaxoredaxo
5.18.2 ≤
𝑥
< 5.21.1
CNA
Common Weakness Enumeration
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