CVE-2025-43855: Trpc

High severity, CVSS 8.7. EPSS: 0.4% chance of exploitation in the next 30 days.

tRPC allows users to build & consume fully typesafe APIs without schemas or code generation. In versions starting from 11.0.0 to before 11.1.1, an unhandled error is thrown when validating invalid connectionParams which crashes a tRPC WebSocket server. This allows any unauthenticated user to crash a tRPC 11 WebSocket server. Any tRPC 11 server with WebSocket enabled with a createContext method set is vulnerable. This issue has been patched in version 11.1.1.

Affected products

• Trpc Trpc: from 11.0.0, before 11.1.1 (fixed in 11.1.1)

Published 2025-04-24. Last modified 2026-06-17.