8.7

CVE-2026-91122

Discourse: Chat MessageBus delivers read-restricted messages to unauthorized users

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the video placeholder component allowed crafted HTML to cause an attribute breakout and inject an attacker-controlled event handler. An authenticated user with default trust-level posting privileges could store the crafted placeholder in a post. When another user opened the post and clicked the video play overlay, the handler could execute arbitrary JavaScript in the viewer's session. Default Content Security Policy settings block inline event handlers, but instances with CSP disabled or relaxed could allow the script to read page content and make authenticated requests as the viewer. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellerdiscourse
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Produkt discourse
Version < 2026.8.0
Status affected
Version >= 2026.7.0-latest, < 2026.7.2
Status affected
Version >= 2026.6.0-latest, < 2026.6.3
Status affected
Version >= 2026.1.0-latest, < 2026.1.8
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.26% 0.159
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 8.7 2.3 5.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product 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.

https://github.com/discourse/discourse/pull/42882
https://github.com/discourse/discourse/security/advisories/GHSA-8m44-f6g9-7cg7
https://github.com/discourse/discourse/commit/05d92b8749f68d2626cbe65ec7adde7562a0283d
https://github.com/discourse/discourse/commit/5674b3e6594825c28d2678e55057fd6802f11031
https://github.com/discourse/discourse/commit/c3993e318e172389be5c98455177876f1dd87dda
https://github.com/discourse/discourse/commit/d7126af3264b672d2201d84c18a37cb8627424a8