CVE-2026-55674
Discourse is an open-source discussion platform.
Impact
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.
Affected products
| Product | Affected versions |
|---|---|
| Discourse Is An Open-Source Discussion Platform. | before 2026.1.6 |
Versions were read from the advisory text. No structured product data has been published for this record yet.