Arbitrary file upload in Redaxo Core
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.
Vulnerability class: Unrestricted File Upload
EPSS: 0.004 (33.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Redaxo Core — versions >= 5.18.2, < 5.21.1
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-53599?
- CVE-2026-53599 is a high-severity vulnerability in Redaxo Core, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 7.5/10. Published 2026-07-31.
- How severe is CVE-2026-53599?
- High severity. CVSS v3 base score is 7.5 out of 10.