Vulnerability from bitnami_vulndb
Published
2026-08-21 11:26
Modified
2026-08-21 11:49
Summary
Discourse: Cache poisoning/XSS via color scheme cookies
Details

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.

To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Bitnami",
        "name": "discourse",
        "purl": "pkg:bitnami/discourse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2026.1.6"
            },
            {
              "introduced": "2026.5.0"
            },
            {
              "fixed": "2026.5.2"
            },
            {
              "introduced": "2026.6.0"
            },
            {
              "fixed": "2026.6.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55674"
  ],
  "database_specific": {
    "cpes": [
      "cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:*",
      "cpe:2.3:a:discourse:discourse:*:*:*:*:beta:*:*:*"
    ],
    "severity": "Critical"
  },
  "details": "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\u0027s nonce-based Content Security Policy, resulting in arbitrary JavaScript execution in visitors\u0027 browsers. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.",
  "id": "BIT-discourse-2026-55674",
  "modified": "2026-08-21T11:49:56.463Z",
  "published": "2026-08-21T11:26:39.921Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-qx4v-rg4v-pm2g"
    },
    {
      "type": "WEB",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55674"
    }
  ],
  "schema_version": "1.6.2",
  "summary": "Discourse: Cache poisoning/XSS via color scheme cookies"
}



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