CVE-2026-39386: Github.com/m1k1o/neko/server Neko Has A Self-service Privilege Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2gw9-c2r2-f5qf",
  "modified" : "2026-06-09T10:52:18Z",
  "published" : "2026-04-21T17:24:42Z",
  "aliases" : [ "CVE-2026-39386" ],
  "summary" : "Neko has a Self-service Privilege Escalation for Authenticated Users",
  "details" : "### Impact\n\nAny authenticated user can immediately obtain full administrative control of the entire Neko instance (member management, room settings, broadcast control, session termination, etc.). This results in a complete compromise of the instance.\n\n### Patches\n\nThe vulnerability has been patched in the following releases:\n\n- [v3.0.11](https://github.com/m1k1o/neko/releases/tag/v3.0.11) (backport release)\n- [v3.1.2](https://github.com/m1k1o/neko/releases/tag/v3.1.2) (latest stable release)\n\nUsers should upgrade to [v3.0.11](https://github.com/m1k1o/neko/releases/tag/v3.0.11) or later (for the 3.0 branch) or [v3.1.2](https://github.com/m1k1o/neko/releases/tag/v3.1.2) or later.\n\n### Workarounds\n\nIf upgrading is not immediately possible, the following mitigations can reduce risk:\n\n- Restrict access to trusted users only (avoid granting accounts to untrusted parties)\n- Run the instance only when needed; avoid leaving it continuously exposed\n- Disable or restrict access to the `/api/profile` endpoint if feasible\n- Monitor for suspicious privilege changes or unexpected administrative actions\n\nNote: These are temporary mitigations and do not fully eliminate the vulnerability. Upgrading is strongly recommended.\n\n### Credits\nNeko thanks @blitzkrieg-patch for responsibly disclosing this vulnerability and reaching out directly. This contribution helped strengthen the project, and the whole community benefits from it.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/m1k1o/neko/server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.11"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/m1k1o/neko/server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.0.0-20250322225643-212bf8a60756"
      }, {
        "fixed" : "0.0.0-20260406184107-c54bcf1ee211"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/m1k1o/neko/security/advisories/GHSA-2gw9-c2r2-f5qf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39386"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/m1k1o/neko/commit/6b561feb9016badea99ae7305091c0ff55e1d114"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/m1k1o/neko/commit/c54bcf1ee211e28104a2bb6db59583a39c4a4d6e"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/m1k1o/neko"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/m1k1o/neko/releases/tag/v3.0.11"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/m1k1o/neko/releases/tag/v3.1.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-20", "CWE-269", "CWE-284", "CWE-639", "CWE-862" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-21T17:24:42Z",
    "nvd_published_at" : "2026-04-21T01:16:06Z"
  }
}