{"data":{"id":"4ef496ad-d5ce-4f43-b7b0-5be62c8c540e","title":"GHSA-5h93-6whr-6q8j: Model Context Protocol Python SDK: HTTP client transports followed cross-origin redirects carrying custom headers and bodies","summary":"The Model Context Protocol Python SDK's Streamable HTTP and SSE client transports, and its OAuth client providers, followed HTTP redirects to any host. Custom headers such as an X-API-Key credential were sent to the redirect target, and on 307 or 308 redirects the request body was re-sent too, while a lone Authorization bearer header was dropped by the HTTP library. Affected versions are 1.8.0 through 1.29.1 and 2.0.0 through 2.1.1, and exploitation requires a trusted endpoint to redirect to a different origin.","solution":"Upgrade to mcp 1.30.0 (1.x) or 2.2.0 (2.x) or later; no code changes are needed. Until upgrading, supply your own HTTP client with follow_redirects left at False (http_client= on streamable_http_client; httpx_client_factory= on sse_client and streamablehttp_client), and rotate any credentials a client may have sent to a host you do not control.","labels":["security"],"sourceUrl":"https://github.com/advisories/GHSA-5h93-6whr-6q8j","publishedAt":"2026-10-27T21:05:34.000Z","cveId":"CVE-2026-116685","cweIds":null,"cvssScore":null,"cvssSeverity":"medium","severity":"medium","attackType":["other"],"issueType":"vulnerability","affectedPackages":["mcp@>= 1.8.0, < 1.30.0 (fixed: 1.30.0)","mcp@>= 2.0.0, < 2.2.0 (fixed: 2.2.0)"],"affectedPackageNames":["mcp"],"affectedPackageRefs":["pypi:mcp"],"affectedVendors":["Anthropic"],"affectedVendorsRaw":["Model Context Protocol Python SDK","MCP"],"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":"2026-10-28T00:05:48.678Z","kevDateAdded":null,"advisoryAliases":["GHSA-5h93-6whr-6q8j"],"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":true,"disclosureDate":"2026-10-27T21:05:34.000Z","capecIds":null,"crossRefCount":0,"attackSophistication":"moderate","impactType":["confidentiality"],"aiComponentTargeted":"api","llmSpecific":false,"classifierConfidence":0.85,"researchCategory":null,"atlasIds":null}}