{"action":"Upgrade mcp to 0.23.0 or later.","affected":[{"fixed":"0.23.0","introduced":"0"}],"component":"mcp","cve_ids":["CVE-2026-67431"],"ecosystem":"RubyGems","epss":0.00363,"exploited":false,"fixed_versions":["0.23.0"],"ghsa_id":"GHSA-5p9g-j988-pcwv","id":"tcs_01M5KEH2TGBE8QXF3TAVW1WZJY","modified_at":"2026-07-30T15:00:31.159150886Z","published_at":"2026-07-30T14:44:28Z","references":["https://osv.dev/vulnerability/GHSA-5p9g-j988-pcwv","https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-5p9g-j988-pcwv","https://nvd.nist.gov/vuln/detail/CVE-2026-67431","https://github.com/modelcontextprotocol/ruby-sdk/commit/35466605319a34e4c7808712ae9bb1ca1afb2356","https://github.com/modelcontextprotocol/ruby-sdk","https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0"],"severity":{"label":"high","score":8.3},"sources":[{"source":"osv","source_id":"GHSA-5p9g-j988-pcwv","url":"https://osv.dev/vulnerability/GHSA-5p9g-j988-pcwv"},{"source":"nvd","source_id":"CVE-2026-67431","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67431"}],"summary":"MCP Ruby SDK: Ruby SSE Session Poisoning"}