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MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood

MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood

CVE-2026-67430Published 6 days agoUpdated 6 days agoSource: OSV

Affected packages

  • mcpbefore 0.23.0

Exploit signal

Known exploited (CISA KEV)
No
EPSS score
0.29%
EPSS percentile
21.4%

EPSS is the probability a CVE is exploited in the wild; percentile is its rank among all CVEs. This advisory is in the top 21%.

MCP Ruby SDK: Unbounded session retention in StreamableHTTPTransport allows memory exhaustion via initialize flood | HackTribune