Discourse: Stored XSS via unescaped actor name in post actions
10Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.4
exploitation probability
—
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Affected products
discourse · discourse