metatool-ai MetaMCP up to 2.4.22 Session Store session-lifetime-manager.ts getSession mcp-session-id resource injection

Summaryinfo

A vulnerability was found in metatool-ai MetaMCP up to 2.4.22 and classified as critical. Impacted is the function getSession of the file session-lifetime-manager.ts of the component Session Store. The manipulation of the argument mcp-session-id results in resource injection. This vulnerability is reported as CVE-2026-79537. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in metatool-ai MetaMCP up to 2.4.22. It has been classified as critical. Affected is the function getSession of the file session-lifetime-manager.ts of the component Session Store. The manipulation of the argument mcp-session-id with an unknown input leads to a resource injection vulnerability. CWE is classifying the issue as CWE-99. The product receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is traded as CVE-2026-79537 since 08/25/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/29/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• metatool-ai

Name

• MetaMCP

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3
• 2.4.4
• 2.4.5
• 2.4.6
• 2.4.7
• 2.4.8
• 2.4.9
• 2.4.10
• 2.4.11
• 2.4.12
• 2.4.13
• 2.4.14
• 2.4.15
• 2.4.16
• 2.4.17
• 2.4.18
• 2.4.19
• 2.4.20
• 2.4.21
• 2.4.22

CPE 2.3info

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CPE 2.2info

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