CVE-2026-59830
Medium
Description
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.
SeverityMedium
CVSS5.4
Exploit probability—
Product
Discourse
PublishedSep 21, 2026
First seenSep 21, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| discourse discourse | < 2026.7.0 | — |
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