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CVE PROGRAM SOURCE RECORD6.2 Medium

CVE-2026-63119

MCP Ruby SDK: Unbounded line buffer in stdio transports leads to memory exhaustion (DoS)

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Status
Published
Published
Updated
Assigning organization
GitHub_M

Description

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StdioTransport and MCP::Client::Stdio in the mcp gem use IO#gets without a byte limit, allowing a peer that sends data without a newline to exhaust process memory. This issue is fixed in version 0.23.0.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

modelcontextprotocol ruby-sdk

  • < 0.23.0affected

References