CVE-2026-54685 FileBrowser Quantum has Username Enumeration via Authentication Timing Side-Channel
Attackers can enumerate valid usernames by measuring response time differences in the login endpoint, exposing user account existence.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54685?
CVE-2026-54685 is a medium-severity vulnerability in gtsteffaniak filebrowser, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
FileBrowser Quantum is a free, self-hosted, web-based file manager. Prior to version 1.3.2-beta, the `/api/auth/login` authentication endpoint does not execute in constant time. When a non-existent username is supplied, the server returns a `401`/`403` response almost immediately. When a valid username is provided, the server performs a bcrypt password comparison, causing a measurable delay in the response time. Version 1.3.2-beta patches the issue.
Weakness: CWE-208
Which versions are affected by CVE-2026-54685?
3 open source packages ship an affected version, including github.com/gtsteffaniak/filebrowser/backend.
| Package | Affected | Fixed in |
|---|---|---|
github.com/gtsteffaniak/filebrowser/backend Go | All versions | 0.0.0-20260317230626-af08800667b8 |
github.com/gtsteffaniak/filebrowser/backend Go | All versions | 0.0.0-20260317230626-af08800667b8 |
github.com/gtsteffaniak/filebrowser/backend Go | All versions | 0.0.0-20260317230626-af08800667b8 |
How do I fix CVE-2026-54685?
Upgrade github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260317230626-af08800667b8 or later.
Is CVE-2026-54685 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54685 exists.
Sources
Also known as GHSA-7789-65hx-f26w, GO-2026-4820.