GHSA-8r9q-7v3j-jr4g Anthropic's MCP TypeScript SDK has a ReDoS vulnerability

• npm @modelcontextprotocol/sdk: >= 1.3.0, < 1.25.2 → fixed in 1.25.2

Impact A ReDoS vulnerability in the `UriTemplate` class allows attackers to cause denial of service. The `partToRegExp()` function generates a regex pattern with nested quantifiers (`([^/]+(?:,[^/]+)*)`) for exploded template variables (e.g., `{/id*}`, `{?tags*}`), causing catastrophic backtracking on malicious input. Who is affected: MCP servers that register resource templates with exploded array patterns and accept requests from untrusted clients. Attack result: An attacker sends a crafted URI via `resources/read` request, causing 100% CPU utilization, server hang/crash, and denial of service for all clients. Affected Versions All versions of `@modelcontextprotocol/sdk` prior to the patched release. Patches v1.25.2 contains b392f02ffcf37c088dbd114fedf25026ec3913d3 the fix modifies the regex pattern to prevent backtracking. Workarounds • Avoid using exploded patterns (`{/id*}`, `{?tags*}`) in resource templates • Implement request timeouts and rate limiting • Validate URIs before processing to reject suspicious patterns