CVE catalog

CVE-2026-33946

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDK's streamable_http_transport.rb implementation contains a session hijacking vu

[CVE catalog]

Severity
High · CVSS 8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
Source
[NVD] · [CVE record]
EPSS
0.47% · Oct 25, 2026

MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to version 0.9.2, the Ruby SDK's streamable_http_transport.rb implementation contains a session hijacking vulnerability. An attacker who obtains a valid session ID can completely hijack the victim's Server-Sent Events (SSE) stream and intercept all real-time data. Version 0.9.2 contains a patch.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

DistributionPackageReleaseVersionStatus
Cpemcp_ruby_sdkNot reported0.9.2fixed
Cpemcp_ruby_sdkNot reported0.9.2fixed

Fixed-version evidence

DistributionPackageTypeReleaseFixed versionUrgencyOriginBugs
Cpemcp_ruby_sdkcpeNot reported0.9.2Not reportedNot reportedNot reported
Cpemcp_ruby_sdkcpeNot reported0.9.2Not reportedNVD-CVE-2026-33946Not reported

OpenFactory catalog packages

No matching packages in this catalog.

Observed:

References

[FIRST EPSS] · [National Vulnerability Database (NVD)]