CVE-2026-67432
High
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 reads and parses an entire JSON-RPC POST body without a size limit, allowing an unauthenticated remote attacker to exhaust process memory. This issue is fixed in version 0.23.0.
SeverityHigh
CVSS7.5
Exploit probability—
ProductModelcontextprotocol Ruby-sdk
PublishedJul 29, 2026
First seenJul 29, 2026
Weakness typeCWE-770Allocation of resources without limits
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| modelcontextprotocol ruby-sdk | < 0.23.0 | — |
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