CrossSite Scripting in Discourse Post Action (<2026.7.0)
CVE-2026-59830 Published on September 21, 2026
Discourse: Stored XSS via unescaped actor name in post actions
Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in another user's browser. This issue is fixed in version 2026.7.0.
Vulnerability Analysis
CVE-2026-59830 is exploitable with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-59830 has been classified to as a XSS vulnerability or weakness.
Products Associated with CVE-2026-59830
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