Medium severity5.9NVD Advisory· Published Mar 27, 2026· Updated Apr 2, 2026
CVE-2026-33946
CVE-2026-33946
Description
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
mcpRubyGems | < 0.9.2 | 0.9.2 |
Affected products
2Patches
Vulnerability mechanics
References
11- github.com/modelcontextprotocol/csharp-sdk/blob/main/src/ModelContextProtocol.AspNetCore/SseHandler.csnvdPatchWEB
- github.com/modelcontextprotocol/go-sdk/blob/main/mcp/streamable.gonvdPatchWEB
- github.com/modelcontextprotocol/python-sdk/blob/main/src/mcp/server/streamable_http.pynvdPatchWEB
- github.com/modelcontextprotocol/ruby-sdk/blob/main/examples/streamable_http_server.rbnvdPatchWEB
- github.com/modelcontextprotocol/ruby-sdk/commit/db40143402d65b4fb6923cec42d2d72cb89b3874nvdPatchWEB
- github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-qvqr-5cv7-wh35nvdExploitVendor AdvisoryWEB
- github.com/advisories/GHSA-qvqr-5cv7-wh35ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-33946ghsaADVISORY
- github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.9.2nvdProductRelease NotesWEB
- github.com/rubysec/ruby-advisory-db/blob/master/gems/mcp/CVE-2026-33946.ymlghsaWEB
- hackerone.com/reports/3556146nvdPermissions RequiredWEB
News mentions
0No linked articles in our index yet.