CVE-2026-63119

MEDIUM SEVERITY

CVSS Score & Metrics

Base Score

6.2 / 10

Vector String

                                        CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H                                    

Vulnerability 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.

Vulnerability Details

Published Date

July 29, 2026

Last Modified

July 29, 2026

CWE ID

CWE-400

Source

NVD

Vendor

modelcontextprotocol

Product

ruby-sdk

External References

https://github.com/modelcontextprotocol/ruby-sdk/commit/267b8fa6285453525c81ce43db6b7dcd7a8a8c2f
https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3w9x-ch42
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-7683-3w9x-ch42

CVE-2026-63119

CVSS Score & Metrics

Vulnerability Description

Vulnerability Details

External References

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