{"id":"CVE-2026-55674","aliases":["BIT-discourse-2026-55674","EUVD-2026-60236","GHSA-qx4v-rg4v-pm2g"],"status":"published","title":"Discourse: Cache poisoning/XSS via color scheme cookies","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.","severity":{"version":"3.1","score":9.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0059,"percentile":0.48529,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-08-17T15:30:17Z","modified":"2026-10-28T02:30:43Z","fixes":[{"ecosystem":"Bitnami","package":"discourse","fixed_in":["2026.1.6","2026.5.2","2026.6.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"discourse","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2026.1.6"},{"introduced":"2026.5.0"},{"fixed":"2026.5.2"},{"introduced":"2026.6.0"},{"fixed":"2026.6.1"}]}]}],"products":[{"vendor":"discourse","product":"discourse"}],"references":[{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-qx4v-rg4v-pm2g","tags":["x_refsource_CONFIRM","web","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55674","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55674.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-55674","title":"Discourse: Cache poisoning/XSS via color scheme cookies","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.","status":"published","published":"2026-08-17T15:30:17.691Z","modified":"2026-08-18T14:43:21.43Z","cvss":[{"version":"3.1","score":9.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","level":"critical","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-60236","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.","status":"published","published":"2026-08-17T15:30:17Z","modified":"2026-08-18T14:43:21Z","cvss":[{"version":"3.1","score":9.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T18:01:46.762528Z"}],"nvd":[{"id":"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.","status":"published","published":"2026-08-17T16:16:58.917Z","modified":"2026-09-18T20:09:01.757Z","cvss":[{"version":"3.1","score":9.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:38.647684Z"}],"osv":[{"id":"CVE-2026-55674","title":"Discourse: Cache poisoning/XSS via color scheme cookies","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.","status":"published","published":"2026-08-17T15:30:17.691Z","modified":"2026-10-28T02:30:43.393874118Z","cvss":[{"version":"3.1","score":9.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:11.22012Z"},{"id":"BIT-discourse-2026-55674","title":"Discourse: Cache poisoning/XSS via color scheme cookies","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.","status":"published","published":"2026-08-21T11:26:39.921Z","modified":"2026-10-05T14:30:06.830484359Z","updated_at":"2026-11-02T15:28:29.152062Z"}]}}