CVE-2026-55424

Description

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.

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