CVE-2026-79537Network attack vectorHinoki check available

Cross-tenant tool access via unbound session IDs

Published Sep 29, 2026 · Updated Sep 29, 2026

Session hijacking in metatool-ai MetaMCP 2.4.22 and earlier allows remote attackers to access private MCP tools via exposed session IDs. The session manager retrieves a transport by the client-supplied mcp-session-id alone, while the health route returns active IDs without a session-owner check. Exploitation requires a reachable health route, an active victim session, and an endpoint the attacker can address; tool calls then run through the victim session.

CVSS severityUnavailable
Unscored
EPSS probability0.31%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Session hijacking in metatool-ai MetaMCP 2.4.22 and earlier allows remote attackers to access private MCP tools via exposed session IDs. The session manager retrieves a transport by the client-supplied mcp-session-id alone, while the health route returns active IDs without a session-owner check. Exploitation requires a reachable health route, an active victim session, and an endpoint the attacker can address; tool calls then run through the victim session.

The record

CVE
CVE-2026-79537
Published
Sep 29, 2026
Updated
Sep 29, 2026
Vendor
metatool-ai
Product
MetaMCP
Classifications
T1550
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

metatool-ai · MetaMCPversion=n/a

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1550Use Alternate Authentication Material

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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