CVE-2026-67432

RubyGems/mcp CVE-2026-67432: high 7.5, EPSS 0.78%

MCP Ruby SDK: Unbounded JSON-RPC request body causes uncontrolled memory allocation in StreamableHTTPTransport

Action: Upgrade mcp to 0.23.0 or later.

bundle update mcp

Affected

Fixed versions

Sources

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

CVE-2026-67432 · published 2026-07-30T14:44:06Z · modified 2026-07-30T15:00:31.539613886Z · JSON