CVE-2025-32391: hedgedoc XSS — Fix

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.

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CVSS v3.1 Score

6.4

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
hedgedoc	hedgedoc	< 1.10.3

References

Advisories & Patches

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

Frequently Asked Questions

What is CVE-2025-32391? +

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. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2025-32391? +

CVE-2025-32391 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-32391? +

CVE-2025-32391 affects products from hedgedoc, specifically: hedgedoc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-32391? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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