CVE-2026-67430
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 expire sessions by default, so repeated initialize requests retain unbounded ServerSession objects and can exhaust process memory. This issue is fixed in version 0.23.0.
- CVSS 3.1
- 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)
- CWEs
- CWE-401, CWE-770
- Published
- Modified
- Record from
- the NVD, synced
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-52jp-gj8w-j6xh | RubyGems | mcp | <0.23.0 | 0.23.0 |
References
- https://github.com/modelcontextprotocol/ruby-sdk/commit/afb968c468c178c4d3294b423fcce250621692f4
- https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-52jp-gj8w-j6xh
- https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-52jp-gj8w-j6xh