CVE-2026-53962

EUVD-2026-42734
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.
Cross-site Scripting
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.4 MEDIUM
NETWORK
LOW
LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 22.59%
Affected Products (NVD)
VendorProductVersion
discoursediscourse
2026.1.0 ≤
𝑥
< 2026.1.5
discoursediscourse
2026.4.0 ≤
𝑥
< 2026.4.2
discoursediscourse
2026.5.0 ≤
𝑥
< 2026.5.1
discoursediscourse
2026.6.0
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://github.com/discourse/discourse/commit/3ee8343cd7f00d59d8513bee0a12e02d50bfc358
https://github.com/discourse/discourse/commit/810c2715799fd08b06fd6ffc664d9562fe9ea6ff
https://github.com/discourse/discourse/commit/92a699d89b84685b6fdd63cd0d0e371793c69dad
https://github.com/discourse/discourse/commit/b8ceb49f4ba52257be30eb3c2ce51a5bf03be5fe
https://github.com/discourse/discourse/releases/tag/v2026.1.5
https://github.com/discourse/discourse/releases/tag/v2026.4.2
https://github.com/discourse/discourse/releases/tag/v2026.5.1
https://github.com/discourse/discourse/releases/tag/v2026.6.0
https://github.com/discourse/discourse/security/advisories/GHSA-jmcf-3367-78vv