CVE-2026-67432

modelcontextprotocol ruby-sdkVulnerabilityCVSS 7.5

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 reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.

No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.

Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.

CVE-2026-67432 modelcontextprotocol ruby-sdk Vulnerability

Severity metrics

CVSS 3.1 : 7.5 HIGH

Attack vectorNetwork (remote)

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

Confidentiality impactNone

Integrity impactNone

Availability impactHigh

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

Affected & fixed versions by distribution

Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.

No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.

Sources

Advisory NVD CVE.org

Published 2026-07-29 · updated 2026-07-30 · source: NVD