Arbitrary file upload in REDAXO - CVE-2026-53599
Published: June 29, 2026
Vulnerability identifier: #VU135821
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-53599
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: REDAXO
Affected software:
REDAXO
REDAXO
Detailed vulnerability description
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to unrestricted upload of file with dangerous type in rex_mediapool::isAllowedExtension and rex_mediapool::filename() when processing uploaded filenames with a blocked extension in a non-terminal segment of a multi-extension chain. A remote user can upload a specially crafted JPEG/PHP polyglot and request it from the public media/ directory to execute arbitrary code.
Exploitation requires backend media upload permission and an Apache PHP handler configuration that matches .php as any segment of the filename.
How to mitigate CVE-2026-53599
Install security update from vendor's website.