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5.4

Discourse image upload can run hidden scripts

CVE-2026-53962 · published 3 months ago
Summary

Older versions of the Discourse forum software could let specially crafted SVG images execute code when someone views them, potentially stealing data or hijacking sessions. This risk is removed in the latest releases. Update Discourse to the newest version as soon as possible to protect your community.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software
VendorProductAffected versions
discourse discourse >= 2026.1.0-latest, < 2026.1.5
Original advisory text
Discourse: Insufficient SVG sanitization logic
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, insufficient SVG sanitization in upload and user avatar handling could lead to cross-site scripting when a user visited specific URLs that are not normally part of community browsing. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
References
Fix within
Internet-facing 60 days
Internal At next upgrade
  • Not known to be exploited
  • Needs hands-on effort to exploit
  • Gives an attacker partial control
Severity
5.4 Medium
Exploitation
<1% chance of attack within 30 days
Type
CWE-79Cross-site Scripting (XSS)
Timeline
Published9 Jul 2026
Updated4 Nov 2026
First seen9 Jul 2026
Sources
CVE-2026-53962 · NVD
CVE-2026-53962 · MITRE
CVE-2026-53962 · OSV
GHSA-jmcf-3367-78vv · GHSA
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