FileBrowser Vulnerable to Stored XSS via SVG File in Public Share (Missing CSP Header)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.4 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

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 1. Login as any user with upload permission 2. Upload SVG file: 3. Create public share for the file 4. Access the share link with ?inline=true 5. JavaScript executes…

Published by the source

7 May 2026, 03:29 UTC

Last modified by the source

7 May 2026, 03:29 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-mmpx-jh39-wrv6

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# Patch Next advisory brief: GHSA-mmpx-jh39-wrv6

Advisory: FileBrowser Vulnerable to Stored XSS via SVG File in Public Share (Missing CSP Header)
IDs: GHSA-mmpx-jh39-wrv6
Record: https://patchnext.com/advisories/ghsa-mmpx-jh39-wrv6 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/gtsteffaniak/filebrowser 0.0.0-20260501184955-6bfc3974192e. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/gtsteffaniak/filebrowser: affected < 0.0.0-20260501184955-6bfc3974192e; fixed in 0.0.0-20260501184955-6bfc3974192e

## Suggested inspection (read-only)
- Go github.com/gtsteffaniak/filebrowser: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/gtsteffaniak/filebrowser.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-mmpx-jh39-wrv6 (GitHub-reviewed advisory GHSA-mmpx-jh39-wrv6 lists affected ranges: Go github.com/gtsteffaniak/filebrowser >=0 <0.0.0-20260501184955-6bfc3974192e)

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