CVE-2026-54685 is a medium-severity (CVSS 5.3) CWE-208 vulnerability in github.com/gtsteffaniak/filebrowser/backend. O3 Security confirms whether CVE-2026-54685 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
FileBrowser Quantum has Username Enumeration via Authentication Timing Side-Channel
Real-World Exposure
github.com/gtsteffaniak/filebrowser/backendReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gtsteffaniak/filebrowser/backend | all versions | 0.0.0-20260317230626-af08800667b8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/gtsteffaniak/filebrowser/backend. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260317230626-af08800667b8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54685 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-54685 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-54685. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-54685 in your dependencies?
O3 detects CVE-2026-54685 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.