CVE-2026-27611 — backend
Fix: gtsteffaniak/filebrowser@c51b0eeCVE-2026-27611 is a Information Exposure vulnerability in github.com/gtsteffaniak/filebrowser/backend. A fix is available for github.com/gtsteffaniak/filebrowser/backend — see the affected versions and patch details below.
FileBrowser Quantum: Password Protection Not Enforced on Shared File Links
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27611.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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 versions 1.1.3-stable and 1.2.6-beta, when users share password-protected files, the recipient can completely bypass the password and still download the file. This happens because the API returns a direct download link in the details of the share, which is accessible to anyone with JUST THE SHARE LINK, even without the password. Versions 1.1.3-stable and 1.2.6-beta fix the issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gtsteffaniak/filebrowser/backend | all versions | 0.0.0-20260221163904-dbcfba993b85go get github.com/gtsteffaniak/filebrowser/backend@v0.0.0-20260221163904-dbcfba993b85 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gtsteffaniak/filebrowser/backend to 0.0.0-20260221163904-dbcfba993b85 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27611 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-27611 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-27611. 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-2026-27611 in your dependencies?
O3 Security finds CVE-2026-27611 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.