{"apiVersion":"1.0","identifier":"CVE-2026-55674","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.","publishedAt":"2026-08-17T16:16:58","lastModifiedAt":"2026-08-18T15:16:55","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55674","cvssScore":9.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","epssProbability":0.00356,"riskScore":0.96,"affectedProduct":"Discourse","affectedVersions":"<2026.1.6, <2026.5.2, <2026.6.1, <2026.7.0","vulnerabilityType":"Web app","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-55674","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-55674","en":"https://www.redsauce.net/en/cves/CVE-2026-55674","fr":"https://www.redsauce.net/fr/cves/CVE-2026-55674","pt":"https://www.redsauce.net/pt/cves/CVE-2026-55674","de":"https://www.redsauce.net/de/cves/CVE-2026-55674","sk":"https://www.redsauce.net/sk/cves/CVE-2026-55674","el":"https://www.redsauce.net/el/cves/CVE-2026-55674"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-55674"}}