CVE-2026-53599
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
ProductRedaxo/source
PublishedJul 31, 2026
First seenJul 31, 2026
Weakness typeCWE-434Unrestricted upload of dangerous file type
How to fix
Update
- redaxo/source5.21.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| redaxo/sourcePackagist | 5.18.2 ≤ v < 5.21.1 | 5.21.1 |
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