{"action":"Upgrade mcp to 0.23.0 or later.","affected":[{"fixed":"0.23.0","introduced":"0"}],"component":"mcp","cve_ids":["CVE-2026-63118"],"ecosystem":"RubyGems","epss":0.00239,"exploited":false,"fixed_versions":["0.23.0"],"ghsa_id":"GHSA-rjr6-rcgv-9m7m","id":"tcs_01M5KEN9Q59RHK8H78QVV6VZX0","modified_at":"2026-07-30T14:45:28.029334068Z","published_at":"2026-07-30T14:41:39Z","references":["https://osv.dev/vulnerability/GHSA-rjr6-rcgv-9m7m","https://github.com/modelcontextprotocol/ruby-sdk/security/advisories/GHSA-rjr6-rcgv-9m7m","https://nvd.nist.gov/vuln/detail/CVE-2026-63118","https://github.com/modelcontextprotocol/ruby-sdk/commit/ba543083a7594e7892b29464b89091816446ff7a","https://github.com/modelcontextprotocol/ruby-sdk","https://github.com/modelcontextprotocol/ruby-sdk/releases/tag/v0.23.0"],"severity":{"label":"medium","score":6.9},"sources":[{"source":"osv","source_id":"GHSA-rjr6-rcgv-9m7m","url":"https://osv.dev/vulnerability/GHSA-rjr6-rcgv-9m7m"},{"source":"nvd","source_id":"CVE-2026-63118","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63118"}],"summary":"MCP Ruby SDK: Streamable HTTP transport lacks DNS-rebinding (Host/Origin) protection"}