Getkirby Kirby up to 4.9.4/5.5.1 Media src/Cms/Media.php Kirby\Cms\Media::thumb path traversal

Summaryinfo

A vulnerability was found in Getkirby Kirby up to 4.9.4/5.5.1 and classified as critical. This issue affects the function Kirby\Cms\Media::thumb of the file src/Cms/Media.php of the component Media Handler. Such manipulation leads to path traversal. This vulnerability is listed as CVE-2026-75594. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Getkirby Kirby up to 4.9.4/5.5.1. Affected by this issue is the function Kirby\Cms\Media::thumb of the file src/Cms/Media.php of the component Media Handler. The manipulation with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Kirby is an open-source content management system. Prior to 4.9.5 and 5.5.2, depending on the release line, Kirby's media handler in src/Cms/Media.php allowed Kirby\Cms\Media::thumb() to append a path-bearing filename to a validated parent media directory. On nginx, PHP's built-in server, or Apache with AllowEncodedSlashes enabled, a remote attacker could submit encoded slash characters such as %2f in the filename and traverse outside the parent's media directory. Differences between responses for existing and nonexistent thumbnail configurations disclosed whether an arbitrary .json file existed, and a .json file containing a valid filename key could cause the referenced image to be returned and the job file to be deleted. The related file::version path in src/Filesystem/Asset.php also accepted ../ sequences outside the intended index root. This issue is fixed in versions 4.9.5 and 5.5.2.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-75594 since 08/18/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

By approaching the search of inurl:src/Cms/Media.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 4.9.5 or 5.5.2 eliminates this vulnerability.

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Productinfo

Vendor

• Getkirby

Name

• Kirby

Version

• 4.9.0
• 4.9.1
• 4.9.2
• 4.9.3
• 4.9.4
• 5.5.0
• 5.5.1

Website

• Product: https://github.com/getkirby/kirby/

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