CVE-2025-12419: Github.com/mattermost/mattermost/server/v8 Mattermost Fails To Properly Validate Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3x39-62h4-f8j6",
  "modified" : "2025-12-17T00:41:08Z",
  "published" : "2025-11-27T18:30:25Z",
  "aliases" : [ "CVE-2025-12419" ],
  "summary" : "Mattermost fails to properly validate OAuth state tokens during OpenID Connect authentication",
  "details" : "Mattermost versions 10.12.x <= 10.12.1, 10.11.x <= 10.11.4, 10.5.x <= 10.5.12, 11.0.x <= 11.0.3 fail to properly validate OAuth state tokens during OpenID Connect authentication which allows an authenticated attacker with team creation privileges to take over a user account via manipulation of authentication data during the OAuth completion flow. This requires email verification to be disabled (default: disabled), OAuth/OpenID Connect to be enabled, and the attacker to control two users in the SSO system with one of them never having logged into Mattermost.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost/server/v8"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "8.0.0-20251028000919-d3ed703dc833"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.12.0"
      }, {
        "fixed" : "10.12.2"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.11.0"
      }, {
        "fixed" : "10.11.5"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "10.5.0"
      }, {
        "fixed" : "10.5.13"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/mattermost/mattermost-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "11.0.0"
      }, {
        "fixed" : "11.0.4"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-12419"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/pull/34296"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/15364790cc277cfaa372693d2d5442b87f70fd42"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/364c2203de00fe0d8424b6b46d6f0eeb02a2539a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/46b5c436bb3093cc1da3fa2455f93d4c52389eee"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/c3f4818afe46a7084740e809708ae22641c76d8d"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/mattermost/mattermost/commit/d3ed703dc8330684952eb8d49a375bac6ea7b0c6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-3x39-62h4-f8j6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/mattermost/mattermost"
  }, {
    "type" : "WEB",
    "url" : "https://mattermost.com/security-updates"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287", "CWE-303" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-12-01T23:56:55Z",
    "nvd_published_at" : "2025-11-27T16:15:46Z"
  }
}