{"data":{"id":"93cf634a-9056-41a1-8865-ad4dc939167a","title":"GHSA-6prh-2h8m-c8cw: MCP TypeScript client SDK: HTTP client transports and OAuth requests followed cross-origin redirects and re-sent custom headers and request bodies","summary":"Affected versions of the MCP TypeScript SDK, including @modelcontextprotocol/sdk through 1.31.0 and @modelcontextprotocol/client 2.0.0 through 2.2.0, followed HTTP redirects to any origin in StreamableHTTPClientTransport, SSEClientTransport and the OAuth client functions such as auth(). A cross-origin redirect sent custom headers such as X-API-Key and the mcp-session-id header to the new origin, and on a 307 or 308 response it also sent the request body, including OAuth refresh_token and client_secret values. stdio clients are not affected.","solution":"Upgrade @modelcontextprotocol/sdk to 1.32.0 or later, or @modelcontextprotocol/client to 2.3.0 or later. Redirects are now followed only within the same origin, and not at all in browsers. If a redirect may have reached a host you do not control, rotate the API keys and client_secret and revoke tokens. If you cannot upgrade yet, pass a fetch that refuses redirects, for example (url, init) => fetch(url, { ...init, redirect: 'error' }).","labels":["security"],"sourceUrl":"https://github.com/advisories/GHSA-6prh-2h8m-c8cw","publishedAt":"2026-10-20T18:26:30.000Z","cveId":"CVE-2026-111769","cweIds":null,"cvssScore":null,"cvssSeverity":"medium","severity":"medium","attackType":["other"],"issueType":"vulnerability","affectedPackages":["@modelcontextprotocol/client@>= 2.0.0, < 2.3.0 (fixed: 2.3.0)","@modelcontextprotocol/sdk@< 1.32.0 (fixed: 1.32.0)"],"affectedPackageNames":["@modelcontextprotocol/client","@modelcontextprotocol/sdk"],"affectedPackageRefs":["npm:@modelcontextprotocol/client","npm:@modelcontextprotocol/sdk"],"affectedVendors":["Anthropic"],"affectedVendorsRaw":["MCP TypeScript client SDK","@modelcontextprotocol/sdk","@modelcontextprotocol/client"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":"unknown","epssScore":0,"epssCheckedAt":"2026-10-21T00:11:14.895Z","kevDateAdded":null,"advisoryAliases":["GHSA-6prh-2h8m-c8cw"],"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":true,"disclosureDate":"2026-10-20T18:26:30.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["confidentiality"],"aiComponentTargeted":"api","llmSpecific":false,"classifierConfidence":0.85,"researchCategory":null,"atlasIds":null}}