# 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.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Feb 2026
- **Updated:** 10 Feb 2026
- **Also known as:** GHSA-4mh3-h929-w968, GO-2026-4474

## 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.

Weakness: CWE-863 (Incorrect Authorization), CWE-706 (Use of Incorrectly-Resolved Name or Reference)

## 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 | Ecosystem | 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: Filebrowser Filebrowser.

## How do I fix CVE-2026-25890?

Upgrade github.com/filebrowser/filebrowser/v2 to 2.57.1 or later.

## 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:

- https://github.com/mbanyamer/CVE-2026-25890-FileBrowser-Access-Control-Bypass (github_poc): https://github.com/mbanyamer/CVE-2026-25890-FileBrowser-Access-Control-Bypass

## Other vulnerabilities in filebrowser

- [CVE-2026-32760](https://insights.sbomify.com/CVE-2026-32760/): File Browser Self Registration Grants Any User Admin Access When Default Permissions Include Admin (critical 10.0)
- [CVE-2026-29188](https://insights.sbomify.com/CVE-2026-29188/): File Browser: TUS Delete Endpoint Bypasses Delete Permission Check (critical 9.1)
- [CVE-2023-39612](https://insights.sbomify.com/CVE-2023-39612/): Cross-site scripting in n/a (critical 9.0)
- [CVE-2026-30934](https://insights.sbomify.com/CVE-2026-30934/): FileBrowser Quantum: Stored XSS in public share page via unsanitized share metadata (text/template misuse) (high 8.9)
- [CVE-2021-46398](https://insights.sbomify.com/CVE-2021-46398/): Cross-Site Request Forgery in Filebrowser (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25890 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-25890 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/filebrowser/filebrowser/v2 (Go): affected all versions; fixed in 2.57.1
- github.com/filebrowser/filebrowser/v2 (Go): affected all versions; fixed in 2.57.1
- github.com/filebrowser/filebrowser/v2 (Go): affected all versions; fixed in 2.57.1
- github.com/filebrowser/filebrowser (Go): affected all versions; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-25890/ (Markdown: https://insights.sbomify.com/CVE-2026-25890/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25890
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25890
- OSV: https://osv.dev/vulnerability/CVE-2026-25890

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25890/
Summaries are generated and may contain mistakes; the official description above is the record.