Description
tRPC allows users to build and consume fully typesafe APIs without schemas or code generation. Starting in version 10.27.0 and prior to versions 10.45.3 and 11.8.0, a A prototype pollution vulnerability exists in `@trpc/server`'s `formDataToObject` function, which is used by the Next.js App Router adapter. An attacker can pollute `Object.prototype` by submitting specially crafted FormData field names, potentially leading to authorization bypass, denial of service, or other security impacts. Note that this vulnerability is only present when using `experimental_caller` / `experimental_nextAppDirCaller`. Versions 10.45.3 and 11.8.0 fix the issue.
References1
Metrics
- CVSS 4.0
-
8.5
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:H/VA:L/SC:L/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 34 · as of 11 November 2026
- CWE
- CWE-1321
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.