CVE-2026-55674

Published: Ago 17, 2026 Last Modified: Ago 17, 2026
ExploitDB:
Other exploit source:
Google Dorks:
CRITICAL 9,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: changed
Confidentiality: high
Integrity: high
Availability: none

Description

AI Translation Available

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.

79

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Stable
Abstraction: Base Structure: Simple
Common Consequences
Security Scopes Affected:
Access Control Confidentiality Integrity Availability
Potential Impacts:
Bypass Protection Mechanism Read Application Data Execute Unauthorized Code Or Commands
Applicable Platforms
Technologies: AI/ML, Web Based, Web Server
Likelihood of Exploit: High
View CWE Details
https://github.com/discourse/discourse/security/advisories/…
https://github.com/discourse/discourse/security/advisories/GHSA-qx4v-rg4v-pm2g