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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Lfprojects Mcp_Ruby_Sdk
cpe:2.3:a:lfprojects:mcp_ruby_sdk:*:*:*:*:*:*:*:*
|
— |
0.9.2
|
References 8
https://github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextPr…
security-advisories@github.com
https://github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.go#L281…
security-advisories@github.com
https://github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/str…
security-advisories@github.com
https://github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_…
security-advisories@github.com
https://github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923ce…
security-advisories@github.com
https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2
security-advisories@github.com
https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-…
security-advisories@github.com
https://hackerone.com/reports/3556146
security-advisories@github.com