9.3

CVE-2026-55674

Discourse: Cache poisoning/XSS via color scheme cookies

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, an unauthenticated attacker could send a single request with a crafted color_scheme_id (or dark_scheme_id) cookie to inject arbitrary HTML into a Discourse page. Because the cookie value was rendered into a color scheme tag without escaping, the attacker could break out of the attribute and inject a tag that bypassed Discourse's nonce-based Content Security Policy, resulting in arbitrary JavaScript execution in visitors' browsers. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellerdiscourse
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Produkt discourse
Version < 2026.1.6
Status affected
Version >= 2026.5.0-latest, < 2026.5.2
Status affected
Version >= 2026.6.0-latest, < 2026.6.1
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 0.34% 0.266
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 9.3 2.8 5.8
CVSS:3.1/AV:N/AC:L/PR:N/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/security/advisories/GHSA-qx4v-rg4v-pm2g