What is CVE-2026-67430?

CVE-2026-67430 is a medium-severity vulnerability in Modelcontextprotocol Ruby-sdk, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 5.3/10. Published 2026-07-29.

How severe is CVE-2026-67430?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Resource exhaustion in Modelcontextprotocol Ruby-sdk

CVE-2026-67430

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not expire sessions by default, so repeated initialize requests ret…

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Modelcontextprotocol Ruby-sdk — versions < 0.23.0

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-67430?: CVE-2026-67430 is a medium-severity vulnerability in Modelcontextprotocol Ruby-sdk, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 5.3/10. Published 2026-07-29.
How severe is CVE-2026-67430?: Medium severity. CVSS v3 base score is 5.3 out of 10.