CVE-2026-63119

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CVSS 3.1

6.2 medium

EPSS

<1%p3

Published

Jul 29, 2026 (Jul 29, 2026)

Modified

Jul 30, 2026

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.

Weakness: CWE-400, CWE-770
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD CVE.org GitHub PoCs EPSS (0.1%)

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