MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that execute in the victim's session. This issue is fixed in version 0.23.0.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-5p9g-j988-pcwv | MCP Ruby SDK: Ruby SSE Session Poisoning |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 30 Jul 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Wed, 29 Jul 2026 21:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Modelcontextprotocol
Modelcontextprotocol ruby-sdk |
|
| Vendors & Products |
Modelcontextprotocol
Modelcontextprotocol ruby-sdk |
Wed, 29 Jul 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not bind a session ID to a session owner, allowing an attacker with a stolen session ID to send tools/call requests that execute in the victim's session. This issue is fixed in version 0.23.0. | |
| Title | MCP Ruby SDK: Ruby SSE Session Poisoning | |
| Weaknesses | CWE-284 | |
| References |
| |
| Metrics |
cvssV4_0
|
Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-30T14:35:45.395Z
Reserved: 2026-07-29T15:07:24.991Z
Link: CVE-2026-67431
Updated: 2026-07-30T14:35:38.999Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-07-31T23:15:05Z
Weaknesses
Github GHSA