{"id":"CVE-2026-79537","details":"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.","modified":"2026-10-02T03:31:04.953096447Z","published":"2026-09-29T00:00:00Z","database_specific":{"cna_assigner":"mitre","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/79xxx/CVE-2026-79537.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/79xxx/CVE-2026-79537.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79537"},{"type":"ADVISORY","url":"https://www.traceforce.ai/security-advisories/cve-2026-79537"},{"type":"PACKAGE","url":"https://github.com/metatool-ai/metamcp"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/metatool-ai/metamcp","events":[{"introduced":"0"},{"fixed":"32b6e9813acfc13d1013eb2452be1899d6654bb9"}],"database_specific":{"source":"DESCRIPTION","extracted_events":[{"introduced":"0"},{"fixed":"2.4.22"}]}}],"versions":["v2.4.16","v2.4.21","v2.4.20","v2.4.19","v2.4.18","v2.4.15","v2.4.17","v2.4.14","v2.4.13","v2.4.12","v2.4.11","v2.4.10","v2.4.9","v2.4.8","v2.4.6","v2.4.7","v2.4.5","v2.3.8","v2.3.7","v2.3.6","v2.3.5","v2.3.4","v2.3.3","v2.3.2","v2.3.1","v2.3.0","v2.2.5","v2.2.4","v2.2.3","v2.2.2","v2.2.1","v2.2.0","v2.1.1","v2.1.0","v2.0.6","v2.0.5","v2.0.3","v2.0.2","v2.0.1","v2.0.0","v0.6.0","v0.5.3","v0.5.2","v0.5.0","v0.4.5","v0.4.3","v0.4.2","v0.4.0","v0.3.2","v0.0.2","v0.0.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-79537.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}