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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-248"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/43xxx/CVE-2025-43855.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "11.0.0"
},
{
"fixed": "11.1.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "9beb26c636d44852e0f407f3d7a82ad54df65b4d"
}
],
"source": "REFERENCES_COMMIT"
}
]
}