CVE-2025-43855: tRPC 11 WebSocket DoS Vulnerability

Severity: high (CVSS 8.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-24 · updated 2026-06-17
Weakness: CWE-248

Description

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: from 11.0.0, < 11.1.1

References

https://github.com/trpc/trpc/commit/9beb26c636d44852e0f407f3d7a82ad54df65b4d
https://github.com/trpc/trpc/security/advisories/GHSA-pj3v-9cm8-gvj8

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