CVE-2026-54089 File Browser: Authentication Bypass via Proxy Auth Header Forgery
Attackers can bypass authentication and create accounts by forging proxy headers when proxy authentication is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54089?
CVE-2026-54089 is a critical authentication bypass vulnerability in filebrowser, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Which versions are affected by CVE-2026-54089?
4 open source packages ship an affected version, including github.com/filebrowser/filebrowser/v2 and github.com/filebrowser/filebrowser.
| Package | Affected | Fixed in |
|---|---|---|
github.com/filebrowser/filebrowser/v2 Go | From 2.0.0-rc.1 | None |
github.com/filebrowser/filebrowser/v2 Go | From 2.0.0-rc.1 to 2.63.18 | None |
github.com/filebrowser/filebrowser/v2 Go | From 2.0.0-rc.1 to 2.63.18 | None |
github.com/filebrowser/filebrowser Go | All versions | None |
How do I fix CVE-2026-54089?
Change a configuration setting.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-54089 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54089 exists.
Sources
Also known as GHSA-xqp3-jq6g-x3qm, GO-2026-5966.