CVE-2026-21896
MEDIUM
GHSA-4j78-4xrm-cr2f
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:H/A:N
Lifecycle Timeline
3Description
Kirby is an open-source content management system. From versions 5.0.0 to 5.2.1, Kirby is missing permission checks in the content changes API. This vulnerability affects all Kirby sites where user permissions are configured to prevent specific role(s) from performing write actions, specifically by disabling the update permission with the intent to prevent modifications to site content. This vulnerability does not affect those who have not altered the deviated from default user permissions. This issue has been patched in version 5.2.2.
Analysis
Kirby CMS versions 5.0.0-5.2.1 fail to enforce permission checks in the content changes API, allowing authenticated users with restricted roles to modify site content despite having update permissions disabled. This affects only installations with custom permission configurations designed to prevent write access for specific user roles. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.
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External POC / Exploit Code
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