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CVE-2026-67432

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

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
modelcontextprotocol / ruby-sdkaffected < 0.23.0

CWE

CWE-770

References

ADP enrichment

CISA-ADP

No English description supplied.