Arbitrary File Upload Affecting redaxo/source package, versions >=5.18.2, <5.21.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PHP-REDAXOSOURCE-18506883
- published2 Aug 2026
- disclosed31 Jul 2026
- creditUnknown
Introduced: 31 Jul 2026
NewCVE-2026-53599 (opens in a new tab)How to fix?
Upgrade redaxo/source to version 5.21.1 or higher.
Overview
Affected versions of this package are vulnerable to Arbitrary File Upload in the isAllowedExtension process. An attacker can achieve arbitrary code execution by uploading a specially crafted file with a multi-segment filename containing a blocked extension as a non-terminal segment, which bypasses extension checks and allows execution of embedded PHP code on servers configured with non-anchored multi-extension handlers. This is only exploitable if the web server is configured to process PHP files based on any segment in the filename (such as Apache mod_php with AddHandler or FilesMatch regex without an end anchor), and the attacker has authenticated backend access with media upload permissions.