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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| modelcontextprotocol | ruby-sdk | affected |
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History
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 | |
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| Metrics |
cvssV4_0
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-29T19:15:32.340Z
Reserved: 2026-07-29T15:07:24.991Z
Link: CVE-2026-67431
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Redhat
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Weaknesses