GHSA-89cp-7p28-jffg CVE-2026-54004
Kirby: Access to files of top-level drafts is not protected by permissions
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.50%
- Chance of exploitation in the next 30 days. Higher than 42.58% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-862 Missing Authorization
- Fix
4.9.4- Upgrade getkirby/cms to this version or later
Description
TL;DR
This vulnerability affects Kirby 5 sites that have the content.fileRedirects option enabled (set to true or a custom closure) as well as all Kirby 4 sites that haven't explicitly disabled this option.
It was possible to access clean file URLs of top-level drafts (e.g. /about-us/team.jpg) without providing authentication, without being authorized to access the top-level draft page, and without providing a valid preview token.
Sites on Kirby 5 using the default configuration are not affected by this vulnerability (the content.fileRedirects option is disabled by default since Kirby 5.0.0). It was also not possible to maliciously access clean file URLs for files stored in page drafts that are not on the top-level (such as /blog/article/resource.pdf).
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
Clean file redirects allow visitors to access files stored in the content folder via natural URLs such as /about-us/team.jpg or /blog/article/resource.pdf. Kirby detects such requests and redirects them to the actual physical file URLs in the media folder.
Kirby 4.8.0 introduced the content.fileRedirects option that allowed disabling this behavior to protect against third-party access to original source files. Kirby 5.0.0 then made the secure behavior (disabled option) the default. It is also possible to set the option to a closure to dynamically control access for each individual file.
Files can be stored in pages. Pages can exist as drafts. In this draft state, the page preview is only accessible to users who are authenticated and authorized by the pages.access permission or to visitors who have received the direct preview URL with a valid preview token.
Impact
In affected releases, the clean file redirects didn't take access logic for drafts into account. When a file stored in a draft page was accessed via its clean file URL, Kirby immediately redirected to the physical media URL without first checking whether the draft page was accessible to the user or visitor. This only affected top-level drafts (direct children of the site) because clean file URLs currently don't work for drafts that are nested under another page.
The unauthorized clean file URL redirects for files in top-level drafts can lead to disclosure of sensitive information or data, e.g., ahead of the launch of a new product or post.
A successful attack requires knowledge of the full path to the draft page and file, and therefore requires knowing the full clean file URL.
Patches
The problem has been patched in Kirby 4.9.4 and Kirby 5.4.4. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, we added an authorization check to the route that redirects clean file URLs of drafts. This route now performs the same checks as the draft preview route, i.e., it only performs the redirect if a user is logged in and has the pages.access permission on the draft, or if a valid preview token was provided in the request URL.
Credits
Thanks to @adamyordan for responsibly reporting the identified issue.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| getkirby/cms | < 4.9.4 |
4.9.4 |
| getkirby/cms | >= 5.0.0-alpha.1, < 5.4.4 |
5.4.4 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
getkirby/cms Packagist → 4.9.4
- composer
composer require getkirby/cms:^4.9.4
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-862: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-9vx2-j98c-p72w Kirby: Access to image files and limited access to JSON files outside of the site root via path traversal in the media handling | High | Also affects getkirby/cms |
| GHSA-6j4c-mgqr-qv76 Kirby: Access to image files outside of the site root via path traversal in the media handling | Medium | Also affects getkirby/cms |
| GHSA-67mx-6wf2-92xp Kirby: File upload permissions are not checked during processing of chunk data | High | Also affects getkirby/cms |
| GHSA-rf2p-vh74-7vvh Kirby: System path exposure from error messages in the REST API | Medium | Also affects getkirby/cms |
| GHSA-r3w8-2c5r-h9j9 Kirby: `pages.access` permission is not checked in the `site/find` REST API route | High | Also affects getkirby/cms |
| GHSA-whxw-24jc-cwmv Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header | Critical | Also affects getkirby/cms |
| GHSA-wr9h-4r83-f4v6 Kirby: Cross-site scripting (XSS) from incomplete HTML/XML sanitization in `Dom::sanitize()` | High | Also affects getkirby/cms |
| GHSA-4v4h-m2qq-ppgw Kirby: Request header injection in `Http\Remote` | Medium | Also affects getkirby/cms |
MergeHarbor checks every repository's dependencies against this database, ranks what matters by exploitability and reachability, routes it to the owning team and opens the fix pull request.
Check your repos with MergeHarbor