# CVE-2025-43855

## Summary

- **CVE ID:** CVE-2025-43855
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)
- **CWE:** CWE-248
- **Published:** Apr 24, 2025
- **Last Modified:** Mar 13, 2026

## 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 — trpc (>= 11.0.0, < 11.1.1)

## References

- [CNA](https://github.com/trpc/trpc/security/advisories/GHSA-pj3v-9cm8-gvj8)
- [CNA](https://github.com/trpc/trpc/commit/9beb26c636d44852e0f407f3d7a82ad54df65b4d)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.40%
- **EPSS Percentile:** 33.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._