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CVE-2026-55674 Details

UNDERGOING ENRICHMENT

The CVE is currently being enriched by the Volerion team. The enrichment process results in the association of reference link tags, CVSS, and CPE applicability statement data.

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:…Vector:This vulnerability is currently being analyzed.

CNA: [email protected]CVSS-B:9.3 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/discourse/discourse/security/advisories/GHSA-qx4v-rg4v-pm2g	[email protected]

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-79	Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')	[email protected]

Affected Products

This vulnerability is currently being analyzed

Change History

2 change records found show changes

Date	Action	Recorded By
Aug 18, 2026	CVE Modified	CISA-ADP
Aug 17, 2026	New CVE Received	[email protected]