Vulnerability · Published Jun 25, 2026 · Assigned by GitHub_M
CVE-2026-54089File Browser: Authentication Bypass via Proxy Auth Header Forgery
Critical 9.1
In plain English
A critical-severity improper authentication in filebrowser from filebrowser. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities).
Official description
File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Starting with 2.0.0-rc.1, when FileBrowser is configured with proxy authentication (auth.method=proxy), any unauthenticated attacker who can reach the server directly can impersonate any user - including admin - by sending a single forged HTTP header. No credentials are required. Additionally, specifying a non-existent username causes the server to automatically create a new user account, providing an account creation primitive with no authorization. This is an already known issue that has been documented in the documentation for several years, but has not been documented as a vulnerability before.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/filebrowser/filebrowser | no fix listed | GO-2026-5966 |
| Go | github.com/filebrowser/filebrowser/v2 | no fix listed | GO-2026-5966 |
| Go | github.com/filebrowser/filebrowser/v2 | no fix listed | GHSA-xqp3-jq6g-x3qm |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| filebrowser | filebrowser | >= 2.0.0-rc.1 |
Weakness: CWE-287, CWE-290 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N