CVE-2026-33946

Description

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDKs streamable_http_transport.rb implementation contains a session hijacking vulnerability. An attacker who obtains a valid session ID can completely hijack the victims Server-Sent Events (SSE) stream and intercept all real-time data. Version 0.9.2 contains a patch.

Risk Information

Base Score

5.9

MODERATE

Vector

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

EPSS Score

Exploitation Probability

0.042

Associated Vulnerability

Vulnerability	OS Platform
Vulnerabilities CVE-2026-33946 are fixed in Ruby-mcp 0.9.2	Windows
Vulnerabilities CVE-2026-33946 are fixed in Ruby-mcp for Linux 0.9.2	Linux

Patch Details

No records found

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234