CVE-2026-42174 Kirby: User avatar creation, replacement and deletion are not gated by user update permissions

What is CVE-2026-42174?

CVE-2026-42174 is a medium-severity missing authorization vulnerability in getkirby kirby, published on 9 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, user avatar creation, replacement and deletion are not gated by user update permissions. This issue has been patched in versions 4.9.0 and 5.4.0.

Weakness: CWE-862

Which versions are affected by CVE-2026-42174?

4 open source packages ship an affected version, including getkirby/cms. It affects 1 product.

Products include Getkirby Kirby.

How do I fix CVE-2026-42174?

Upgrade getkirby/cms to a fixed version for your release line: 4.9.0 or 5.4.0.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2026-42174 being exploited?

There is no known exploitation of CVE-2026-42174 in the wild and no public exploit code.

Other vulnerabilities in getkirby kirby

• CVE-2024-26483 Kirby vulnerable to unrestricted file upload of user avatar images High 8.8
• CVE-2024-41964 Insufficient permission checks in the language settings in Kirby CMS High 8.1
• CVE-2026-34587 Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering High 7.6
• CVE-2021-29460 Cross-site scripting (XSS) from unsanitized uploaded SVG files High 7.6
• CVE-2023-38489 Kirby vulnerable to Insufficient Session Expiration after a password change High 7.3

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-39cp-6679-8xv2.