{"id":"CVE-2026-79537","aliases":["EUVD-2026-89362","GHSA-5xqq-w6xh-vwc6"],"status":"published","title":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP...","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp","from":"cve"},"epss":{"day":"2026-11-11","score":0.0031,"percentile":0.24113,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-639"],"published":"2026-09-29T00:00:00Z","modified":"2026-10-28T02:30:30Z","references":[{"url":"https://github.com/metatool-ai/metamcp","tags":["package"]},{"url":"https://www.traceforce.ai/security-advisories/cve-2026-79537","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79537","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-5xqq-w6xh-vwc6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/79xxx/CVE-2026-79537.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-79537","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","status":"published","published":"2026-09-29T00:00:00Z","modified":"2026-09-30T16:45:37.445Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"adp"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T13:50:38.739766Z"}],"euvd":[{"id":"EUVD-2026-89362","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","status":"published","published":"2026-09-29T00:00:00Z","modified":"2026-09-30T16:45:37Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T17:27:48.536397Z"}],"ghsa":[{"id":"GHSA-5xqq-w6xh-vwc6","title":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP...","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","status":"published","published":"2026-09-29T21:33:26Z","modified":"2026-09-30T18:33:19Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T15:12:36.997507Z"}],"nvd":[{"id":"CVE-2026-79537","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","status":"published","published":"2026-09-29T20:17:27.383Z","modified":"2026-09-30T17:32:07.107Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-639"],"updated_at":"2026-11-02T14:12:52.759595Z"}],"osv":[{"id":"CVE-2026-79537","description":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch. The session store (getSession in session-lifetime-manager.ts) is keyed only by the client-supplied mcp-session-id header with no owner, namespace, or endpoint binding, and the per-endpoint authorization middleware validates only the URL endpoint's owner, never the session. An attacker who supplies another tenant's session id \" obtained without authentication from GET /metamcp/health/sessions, which discloses active session IDs and namespace UUIDs \" can list and execute the victim tenant's private MCP tools and exfiltrate their data using the victim's forwarded credentials.","status":"published","published":"2026-09-29T00:00:00Z","modified":"2026-10-28T02:30:30.614932211Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"updated_at":"2026-11-02T15:45:17.44708Z"}]}}