CVSS VectorNVD
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
2DescriptionNVD
Kirby is an open-source content management system. Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (site/blueprints/users/...). It is also possible to customize the permissions for each target model in the model blueprints (such as in site/blueprints/pages/...) using the options feature. The permissions and options together control the authorization of user actions. Kirby provides the pages.create, files.create and users.create permissions (among others). These permissions can again be set in the user blueprint and/or in the blueprint of the target model via options. Prior to versions 4.9.0 and 5.4.0, Kirby allowed to override the options during the creation of pages, files and users by injecting custom dynamic blueprint configuration into the model data. The injected options could include 'create' => true, which then caused an override of the permissions and options configured by the site developer in the user and model blueprints. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. The patched versions have updated the normalization code that is used during the creation of pages, files and users to include a filter for the blueprint property. This prevents the injection of dynamic blueprint configuration into the creation request.
AnalysisAI
Authenticated users in Kirby CMS can bypass permission controls to create unauthorized pages, files, and users by injecting malicious blueprint configuration during model creation. Versions prior to 4.9.0 and 5.4.0 fail to sanitize the 'blueprint' property in creation requests, allowing attackers with low-privilege accounts to override developer-defined authorization policies by setting 'create' => true in dynamic options. …
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RemediationAI
Within 24 hours: Identify all Kirby CMS deployments and document current versions (check composer.json or admin panel). Within 7 days: Upgrade to Kirby 4.9.0 (if on 4.x branch) or 5.4.0 (if on 5.x branch)-test in non-production first. …
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-25371