Summary
Kirby CMS's pages.access permission is not checked during rendering of page drafts
TL;DR
This vulnerability affects all Kirby sites where users of a particular role have no permission to access pages (pages.access permission is disabled). This can be due to configuration in the user blueprint(s), via options in the model blueprint(s) or via a combination of both settings.
Kirby sites are not affected if they intend all users of the site to be able to access all page drafts of the site. The vulnerability can only be exploited by authenticated users. Write actions are not affected by this vulnerability.
Introduction
Missing authorization allows authenticated users to perform actions they are not intended to have access to.
The effects of missing authorization can include unauthorized access to sensitive information as well as unauthorized changes to content or system information.
Affected components
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.access and pages.list permissions (among others). The list permission controls whether affected models appear in lists throughout the Panel and REST API. The access permission has the same effect but also disables direct access to the affected models.
This vulnerability affects the path resolver for the main CMS router. The resolver takes an input path from the requested URL and determines which model (page or file) should be rendered. When a path is requested that points to a page draft, the resolver checks that the request either contains a valid preview token or is authenticated by a valid user.
Credits
Kirby thank to @adrgs for responsibly reporting the identified issue.
Impact
In affected releases, Kirby allowed page drafts to be rendered if any valid user was authenticated, even if that user did not have access to the specific page model. Authenticated attackers with knowledge of the full path to an existing page draft could then access the rendered frontend page. This could lead to the disclosure of sensitive information, e.g. ahead of the launch of a new product or post.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
The problem has been patched in Kirby 4.9.1 and Kirby 5.4.1. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, Kirby has added a check that verifies that the requested page draft is accessible to the current user before rendering the draft template.
Frequently Asked Questions
- What is CVE-2026-44176? CVE-2026-44176 is a medium-severity missing authorization vulnerability in getkirby/cms (composer), affecting versions <= 4.9.0. It is fixed in 4.9.1, 5.4.1. The application does not perform an authorization check before performing a sensitive operation.
- Which versions of getkirby/cms are affected by CVE-2026-44176? getkirby/cms (composer) versions <= 4.9.0 is affected.
- Is there a fix for CVE-2026-44176? Yes. CVE-2026-44176 is fixed in 4.9.1, 5.4.1. Upgrade to this version or later.
- Is CVE-2026-44176 exploitable, and should I be worried? Whether CVE-2026-44176 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-44176 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-44176?
- Upgrade
getkirby/cmsto 4.9.1 or later - Upgrade
getkirby/cmsto 5.4.1 or later
- Upgrade