{"id":"CVE-2026-79537","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-79537","generatedAt":"2026-10-28T00:53:05.786Z","title":"metatool-ai MetaMCP through 2.4.22 contains an insecure direct object reference (IDOR) in the MCP transport session dispatch.","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.","published":"2026-09-29T20:17:27.000Z","lastModified":"2026-09-30T17:32:07.000Z","status":"Deferred","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-639"],"affected":[],"epss":{"score":0.0031,"percentile":0.2361,"date":"2026-10-26","history":[{"date":"2026-09-30","score":0.0018,"percentile":0.0679}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.31%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"scored","label":"Newly scored","at":"2026-09-30T18:45:11.000Z","detail":{"from":null,"score":"9.1","severity":"CRITICAL","fromSeverity":null},"summary":"Now scored CVSS 9.1 CRITICAL."},{"kind":"new","label":"New CVE","at":"2026-09-29T20:17:27.000Z","detail":{"score":null,"severity":null,"publishedAt":"2026-09-29T20:17:27.383Z"},"summary":"New CVE, critical severity (CVSS 9.1)."}],"references":[{"url":"https://github.com/metatool-ai/metamcp","source":"cve@mitre.org"},{"url":"https://www.traceforce.ai/security-advisories/cve-2026-79537","source":"cve@mitre.org"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-79537","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}