Ten security advisories hit the official MCP SDKs in eight days

Ten security advisories were published against the official Model Context Protocol TypeScript SDK (modelcontextprotocol/typescript-sdk) within an eight-day span, according to the repository's GitHub Security Advisories page. The advisories, published by maintainers maxisbey and pcarleton, include high-severity issues such as an OAuth client sending credentials to an authorization server chosen by the MCP server (GHSA-6qxp-vccf-f47h), experimental tasks not tied to the session that created them (GHSA-22jm-h49p-29qw), shared transport or server instances delivering one HTTP client's messages to another (GHSA-jm63-cq47-j5jp), and a single HTTP request within the default size limit exhausting server memory during validation (GHSA-46jr-4wx8-v453). The disclosures matter because the SDK underpins MCP servers and clients that connect AI agents and tools, and the flaws span credential leakage, cross-client data exposure, missing request-size limits and default-disabled DNS rebinding protection on localhost servers (GHSA-w48q-cv73-mx4w).

Repository navigation Security: modelcontextprotocol/typescript-sdk Security Advisories View known security vulnerabilities and report new vulnerabilities privately to maintainers. - OAuth client could send credentials to an authorization server chosen by the MCP server https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-6qxp-vccf-f47h GHSA-6qxp-vccf-f47h publishedSep 30, 2026 by maxisbey https://github.com/maxisbey High - Server bearer authentication accepted tokens issued for another service https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-rvq5-wwqv-78pq GHSA-rvq5-wwqv-78pq publishedOct 5, 2026 by maxisbey https://github.com/maxisbey Moderate - Experimental tasks were not tied to the session that created them https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-22jm-h49p-29qw GHSA-22jm-h49p-29qw publishedOct 2, 2026 by maxisbey https://github.com/maxisbey High - Shared transport or server instances delivered one HTTP client's messages to another https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-jm63-cq47-j5jp GHSA-jm63-cq47-j5jp publishedOct 15, 2026 by maxisbey https://github.com/maxisbey High - HTTP client transports and OAuth requests followed cross-origin redirects and re-sent custom headers and request bodies https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-6prh-2h8m-c8cw GHSA-6prh-2h8m-c8cw publishedOct 2, 2026 by maxisbey https://github.com/maxisbey Moderate - One HTTP request within the default size limit could exhaust server memory during validation https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-46jr-4wx8-v453 GHSA-46jr-4wx8-v453 publishedOct 15, 2026 by maxisbey https://github.com/maxisbey High - HTTP server transports and handlers did not limit request body size or JSON-RPC batch length https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-f897-62hf-6gxq GHSA-f897-62hf-6gxq publishedOct 15, 2026 by maxisbey https://github.com/maxisbey High - Sharing server/transport instances can leak cross-client response data https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7 GHSA-345p-7cg4-v4c7 publishedFeb 4, 2026 by pcarleton https://github.com/pcarleton High - Regular Expression Denial of Service ReDoS in UriTemplate https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-cqwc-fm46-7fff GHSA-cqwc-fm46-7fff publishedJan 7, 2026 by pcarleton https://github.com/pcarleton High - DNS Rebinding Protection Disabled by Default in Model Context Protocol TypeScript SDK for Servers Running on Localhost https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-w48q-cv73-mx4w GHSA-w48q-cv73-mx4w publishedDec 2, 2025 by pcarleton https://github.com/pcarleton High