PT-2026-65899 · Modelcontextprotocol · Ruby-Sdk

CVE-2026-67432 · Published 2026-07-29 · Updated 2026-07-29

Mitre

CVSS v3.1

7.5

High

Base vector

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

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.

Exploit

Fix

Allocation of Resources Without Limits

Weakness Enumeration

CWE-770

Related Identifiers

CVE-2026-67432

Affected Products

Ruby-Sdk

References · 4

• 🔥 https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-h669-8m4g-r2hc · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-67432 · Security Note
• https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0 · Note
• https://github.com/modelcontextprotocol/ruby-sdk/commit/772e0cb1f9db69312006926eee59a7287ad50166 · Note