Vulnerability Details CVE-2026-55424
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, a topic "featured link" was not sufficiently normalized and escaped before being rendered in the topic list, allowing a user who can set a featured link to inject JavaScript when default Content Security Policy protections were modified or disabled. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 18.8%
CVSS Severity
CVSS v3 Score 5.4
References
- https://github.com/discourse/discourse/commit/1bce8881e4253d9bbab56f011a12ef899b926b59
- https://github.com/discourse/discourse/commit/6679d9a5083488bae10c2adbb345c481c583242c
- https://github.com/discourse/discourse/commit/6828aee9b15c2655d63b515ac919830bd540ff83
- https://github.com/discourse/discourse/commit/c9b9405f5bd0bf0269e505e28e3aad388d7657c5
- 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-695w-7fv8-mxg3
Products affected by CVE-2026-55424
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cpe:2.3:a:discourse:discourse:2026.1.0
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cpe:2.3:a:discourse:discourse:2026.1.1
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cpe:2.3:a:discourse:discourse:2026.1.2
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cpe:2.3:a:discourse:discourse:2026.1.3
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cpe:2.3:a:discourse:discourse:2026.1.4
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cpe:2.3:a:discourse:discourse:2026.4.0
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cpe:2.3:a:discourse:discourse:2026.4.1
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cpe:2.3:a:discourse:discourse:2026.6.0