{"id":"CVE-2026-79537","title":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch","summary":"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-…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-639"],"published":"2026-09-29","updated":"2026-09-30","sourceUpdated":"2026-09-30T17:32:07.107","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-79537","references":[{"url":"https://github.com/metatool-ai/metamcp","label":"cve@mitre.org"},{"url":"https://www.traceforce.ai/security-advisories/cve-2026-79537","label":"cve@mitre.org"}],"tags":["nvd","cve.org"],"epss":0.0031,"epssPercentile":0.23671,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-09-30T16:44:55.325385Z"},"ingestedAt":"2026-09-29T19:44:04.162Z","slug":"CVE-2026-79537","body":"## Overview\n\nmetatool-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":213810,"id":"CVE-2026-79537","ts":1790788625690,"field":"cvss","old":null,"new":"9.1"},{"seq":213809,"id":"CVE-2026-79537","ts":1790788625690,"field":"severity","old":"none","new":"critical"}]}