What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-31 · updated 2026-10-23
• Weakness: CWE-434

Description

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.

Affected products

• redaxo core: from 5.18.2, < 5.21.1

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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