CVEvulnerability
CVE-2026-33946
8.2 HIGH
Official page ↗
- Status
- Analyzed
- Published
- 2026-03-27
- Last modified
- 2026-10-26
- Assigner
- [email protected]
- CVSS 4.0 ([email protected])
- 8.2 HIGH — CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- CVSS 3.1 ([email protected])
- 5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weaknesses
- CWE-384, CWE-639
Description
MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDK's streamable_http_transport.rb implementation contains a session hijacking vulnerability. An attacker who obtains a valid session ID can completely hijack the victim's Server-Sent Events (SSE) stream and intercept all real-time data. Version 0.9.2 contains a patch.
Affected configurations
• lfprojects mcp ruby sdk (< 0.9.2)
Related
References
- https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.cs#L93-L97 Patch
- https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281C1-L288C2 Patch
- https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.py#L680-L685 Patch
- https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rb Patch
- https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874 Patch
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2 Product, Release Notes
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35 Exploit, Vendor Advisory
- https://hackerone.com/reports/3556146 Permissions Required
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35 Exploit, Vendor Advisory