VulnerabilityDeferred
CVE-2026-67430
MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients.
MEDIUM 5.3EPSS 0.31%
Does this matter?
Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own.
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 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 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.31% probability · 24th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-401, CWE-770
- Source
- security-advisories@github.com
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.