CVE-2026-59830CWE-79cross-site-scripting

CVE-2026-59830

Medium · published September 22, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
20.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00289 · 20.3th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-09-22T02:16Z
References (3)
https://github.com/discourse/discourse/commit/dd786594ddd088657a7e6f9fefba5bd889965fe4 · [email protected]https://github.com/discourse/discourse/releases/tag/v2026.7.0 · [email protected]https://github.com/discourse/discourse/security/advisories/GHSA-x6mf-p7cg-69rw · [email protected]
EPSS history
Timeline
  • 23 SEP 03:46Z
    EPSS moved — → 0%
    epss
  • 21 SEP 21:17Z
    Discourse: Stored XSS via unescaped actor name in post actions
    cvelistv5