CVE-2026-25890 File Browser has a Path-Based Access Control Bypass via Multiple Leading Slashes in URL
Authenticated users can bypass path restrictions to access restricted files by adding multiple slashes to the URL.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-25890?
CVE-2026-25890 is a high-severity missing authorization vulnerability in filebrowser, published on 9 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
File Browser provides a file managing interface within a specified directory and it can be used to upload, delete, preview, rename and edit files. Prior to 2.57.1, an authenticated user can bypass the application's "Disallow" file path rules by modifying the request URL. By adding multiple slashes (e.g., //private/) to the path, the authorization check fails to match the rule, while the underlying filesystem resolves the path correctly, granting unauthorized access to restricted files. This vulnerability is fixed in 2.57.1.
Which versions are affected by CVE-2026-25890?
4 open source packages ship an affected version, including github.com/filebrowser/filebrowser/v2 and github.com/filebrowser/filebrowser. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/filebrowser/filebrowser/v2 Go | All versions | 2.57.1 |
github.com/filebrowser/filebrowser/v2 Go | All versions | 2.57.1 |
github.com/filebrowser/filebrowser/v2 Go | All versions | 2.57.1 |
github.com/filebrowser/filebrowser Go | All versions | None |
Products include Filebrowser Filebrowser.
How do I fix CVE-2026-25890?
Upgrade github.com/filebrowser/filebrowser/v2 to 2.57.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-25890 being exploited?
There is no known exploitation of CVE-2026-25890 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in filebrowser
- CVE-2026-32760 File Browser Self Registration Grants Any User Admin Access When Default Permissions Include Admin
- CVE-2026-29188 File Browser: TUS Delete Endpoint Bypasses Delete Permission Check
- CVE-2023-39612 Cross-site scripting in n/a
- CVE-2026-30934 FileBrowser Quantum: Stored XSS in public share page via unsanitized share metadata (text/template misuse)
- CVE-2021-46398 Cross-Site Request Forgery in Filebrowser
Sources
Also known as GHSA-4mh3-h929-w968, GO-2026-4474.