CVE-2026-30934 — filebrowser
HIGHCVE-2026-30934 is a high-severity (CVSS 8.9) Cross-site Scripting (XSS) vulnerability in github.com/gtsteffaniak/filebrowser. A fix is available for github.com/gtsteffaniak/filebrowser — see the affected versions and patch details below.
FileBrowser Quantum: Stored XSS in public share page via unsanitized share metadata (text/template misuse)
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.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-30934.
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.
How urgent is this, really
CVE-2026-30934 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/gtsteffaniak/filebrowserReal-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 1.3.1-beta and 1.2.2-stable, Stored XSS is possible via share metadata fields (e.g., title, description) that are rendered into HTML for /public/share/<hash> without context-aware escaping. The server uses text/template instead of html/template, allowing injected scripts to execute when victims visit the share URL. This vulnerability is fixed in 1.3.1-beta and 1.2.2-stable.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gtsteffaniak/filebrowser | all versions | 0.0.0-20260307130210-09713b32a5f6go get github.com/gtsteffaniak/filebrowser@v0.0.0-20260307130210-09713b32a5f6 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/gtsteffaniak/filebrowser to 0.0.0-20260307130210-09713b32a5f6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-30934 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-2026-30934 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-30934. 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-2026-30934 in your dependencies?
O3 Security finds CVE-2026-30934 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.