{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "8.0.3"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "002012cfdbedd2e9b7db9dc83b9f549f761db22e"
            },
            {
              "fixed": "ebb398aeeefaf3bb8b4020237d1b706462d1a00e"
            }
          ],
          "repo": "https://github.com/unleash/unleash",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-w4mq-xh27-6xpx"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-116"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63466.json"
  },
  "details": "Unleash is an open-source feature management platform. Prior to 8.0.3, FeatureEventFormatterMd.format in src/lib/addons/feature-event-formatter-md.ts assigns Mustache.escape to an identity function before rendering action and path templates. Because Mustache.escape is process-wide, the assignment disables escaping for subsequent Mustache.render calls in email-service.ts, webhook.ts, datadog.ts, and new-relic.ts. An editor-level user can place Slack or Microsoft Teams link syntax in an unrestricted username, trigger a feature event, and inject an attacker-labeled link into a trusted outbound notification channel, while other Mustache sinks remain unescaped until restart. This issue is fixed in version 8.0.3.",
  "id": "CVE-2026-63466",
  "modified": "2026-08-23T03:42:42.964633571Z",
  "published": "2026-08-21T18:21:46.526Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Unleash/unleash/releases/tag/v8.0.3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63466.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/Unleash/unleash/security/advisories/GHSA-w4mq-xh27-6xpx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63466"
    },
    {
      "type": "FIX",
      "url": "https://github.com/Unleash/unleash/commit/002012cfdbedd2e9b7db9dc83b9f549f761db22e"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Unleash: Global Mustache.escape override disables HTML escaping process-wide, enabling Slack/Teams link-injection via unrestricted username"
}