Vulnerability Database

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Total vulnerabilities in the database

FileBrowser Vulnerable to Stored XSS via SVG File in Public Share (Missing CSP Header) — github.com/gtsteffaniak/filebrowser

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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: <svg xmlns="http://www.w3.org/2000/svg"> <script>alert(document.domain)</script> </svg>
  3. Create public share for the file
  4. Access the share link with ?inline=true
  5. 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.

  • Published: May 7, 2026
  • Updated: Jun 5, 2026
  • GHSA: GHSA-mmpx-jh39-wrv6
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.4
  • AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Frequently Asked Questions

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CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

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Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

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