CVE-2026-79537

critical · 9.1

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.

9.1

CVSS

0.3%

EPSS (exploit prob.)

22nd

EPSS percentile

2026-09-29

Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Weaknesses

CWE-639

References

https://github.com/metatool-ai/metamcp
https://www.traceforce.ai/security-advisories/cve-2026-79537

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-79537