GHSA-mmpx-jh39-wrv6
MEDIUMGHSA-mmpx-jh39-wrv6 is a medium-severity (CVSS 5.4) vulnerability in github.com/gtsteffaniak/filebrowser. O3 Security confirms whether GHSA-mmpx-jh39-wrv6 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
FileBrowser Vulnerable to Stored XSS via SVG File in Public Share (Missing CSP Header)
Blast Radius
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
Summary
FileBrowser Quantum serves inline SVG files without a Content-Security-Policy header, allowing embedded JavaScript in SVG files to execute when accessed via public share links.
Verified on v1.3.0-stable.
Affected product
- Product: FileBrowser Quantum (
gtsteffaniak/filebrowser) - Verified version: v1.3.0-stable
- Docker image: gtstef/filebrowser:latest
- Affected endpoint:
GET /public/api/resources/download?hash=HASH&inline=true - CWE: CWE-79 — Cross-site Scripting (Stored)
Impact
- Stored XSS — Malicious SVG persists and executes for every visitor to the share link
- No authentication required to trigger — Public share links are accessible to anyone
- Session hijacking — If authenticated users click the link, their session can be stolen
- Phishing — Attacker can redirect or overlay fake login forms
Reproduction
- Login as any user with upload permission
- Upload SVG file:
<svg xmlns="http://www.w3.org/2000/svg"> <script>alert(document.domain)</script> </svg> - Create public share for the file
- Access the share link with
?inline=true - JavaScript executes in browser
Root cause
The inline download endpoint returns SVG files with:
Content-Type: image/svg+xml
Content-Disposition: inline; filename="xss.svg"
X-Content-Type-Options: nosniff
But no CSP header to block script execution. The upstream project (filebrowser/filebrowser) mitigates this with:
Content-Security-Policy: script-src 'none'
Suggested fix
Add CSP header on inline file downloads:
w.Header().Set("Content-Security-Policy", "script-src 'none'")
This matches the upstream filebrowser/filebrowser implementation.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/gtsteffaniak/filebrowser | all versions | 0.0.0-20260501184955-6bfc3974192e |
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. 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 to 0.0.0-20260501184955-6bfc3974192e or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mmpx-jh39-wrv6 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 GHSA-mmpx-jh39-wrv6 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 GHSA-mmpx-jh39-wrv6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-mmpx-jh39-wrv6 in your dependencies?
O3 detects GHSA-mmpx-jh39-wrv6 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.