diff --git a/lib/vocabularies/applicator/oneOf.ts b/lib/vocabularies/applicator/oneOf.ts
index 16eab8ba4..f34c2dc97 100644
--- a/lib/vocabularies/applicator/oneOf.ts
+++ b/lib/vocabularies/applicator/oneOf.ts
@@ -9,7 +9,7 @@ import {_, Name} from "../../compile/codegen"
 import {alwaysValidSchema} from "../../compile/util"
 import {SchemaCxt} from "../../compile"
 
-export type OneOfError = ErrorObject<"oneOf", {passingSchemas: [number, number]}, AnySchema[]>
+export type OneOfError = ErrorObject<"oneOf", {passingSchemas: [number, number] | null}, AnySchema[]>
 
 const error: KeywordErrorDefinition = {
   message: "should match exactly one schema in oneOf",