getkirby Kirby up to 4.9.0/5.4.0 Image Block Link path traversal

Summaryinfo

A vulnerability was found in getkirby Kirby up to 4.9.0/5.4.0 and classified as critical. Impacted is an unknown function of the component Image Block. Such manipulation of the argument Link leads to path traversal. This vulnerability is referenced as CVE-2026-45368. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in getkirby Kirby up to 4.9.0/5.4.0 and classified as critical. Affected by this issue is an unknown code of the component Image Block. The manipulation of the argument link with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-23. The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the underlying URL methods for the KirbyTags and image blocks components did not filter out malicious URL values that resolve to script execution. The vulnerability affects four first-party Kirby renderers that produce `<a href="…">` output from editor-supplied field values: the (`link: …)` KirbyTag, the `link`: parameter of the `(image: …)` KirbyTag when it does not resolve to a known file or `self`, the `link` field of the built-in image block, and the HTML importer for the `blocks` field (which accepted the same malicious input as the image block `link` field). While simple `avascript:` URLs were already deactivated by treating them as a relative path and prepending a single slash to the URL, the use of URLs of the format `javascript://x%0A…` bypasses this protection. The `vbscript:`, `data:`, `livescript:`, `mocha:` and `jar:` schemes are affected by the same underlying gap. This issue has been fixed in versions 4.9.1 and 5.4.1.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-45368 since 05/12/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

Upgrading to version 4.9.1 or 5.4.1 eliminates this vulnerability.

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Productinfo

Vendor

• getkirby

Name

• Kirby

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9.0
• 5.0
• 5.1
• 5.2
• 5.3
• 5.4.0

Website

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

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