diff --git a/Userland/Libraries/LibJS/Runtime/ArrayBuffer.h b/Userland/Libraries/LibJS/Runtime/ArrayBuffer.h
index a00162a284..507a449bcd 100644
--- a/Userland/Libraries/LibJS/Runtime/ArrayBuffer.h
+++ b/Userland/Libraries/LibJS/Runtime/ArrayBuffer.h
@@ -160,7 +160,7 @@ static ByteBuffer numeric_to_raw_bytes(GlobalObject& global_object, Value value,
         if constexpr (IsSigned<UnderlyingBufferDataType>)
             int_value = MUST(value.to_bigint_int64(global_object));
         else
-            int_value = value.to_bigint_uint64(global_object);
+            int_value = MUST(value.to_bigint_uint64(global_object));
 
         ReadonlyBytes { &int_value, sizeof(UnderlyingBufferDataType) }.copy_to(raw_bytes);
         flip_if_needed();
diff --git a/Userland/Libraries/LibJS/Runtime/Value.cpp b/Userland/Libraries/LibJS/Runtime/Value.cpp
index cef553e6e7..2fc03b5483 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.cpp
+++ b/Userland/Libraries/LibJS/Runtime/Value.cpp
@@ -553,9 +553,9 @@ ThrowCompletionOr<i64> Value::to_bigint_int64(GlobalObject& global_object) const
 }
 
 // 7.1.16 ToBigUint64 ( argument ), https://tc39.es/ecma262/multipage/abstract-operations.html#sec-tobiguint64
-u64 Value::to_bigint_uint64(GlobalObject& global_object) const
+ThrowCompletionOr<u64> Value::to_bigint_uint64(GlobalObject& global_object) const
 {
-    auto* bigint = TRY_OR_DISCARD(to_bigint(global_object));
+    auto* bigint = TRY(to_bigint(global_object));
     return bigint->big_integer().to_u64();
 }
 
diff --git a/Userland/Libraries/LibJS/Runtime/Value.h b/Userland/Libraries/LibJS/Runtime/Value.h
index 8febee8c68..e155d34608 100644
--- a/Userland/Libraries/LibJS/Runtime/Value.h
+++ b/Userland/Libraries/LibJS/Runtime/Value.h
@@ -312,7 +312,7 @@ public:
     Value to_number(GlobalObject&) const;
     ThrowCompletionOr<BigInt*> to_bigint(GlobalObject&) const;
     ThrowCompletionOr<i64> to_bigint_int64(GlobalObject&) const;
-    u64 to_bigint_uint64(GlobalObject&) const;
+    ThrowCompletionOr<u64> to_bigint_uint64(GlobalObject&) const;
     double to_double(GlobalObject&) const;
     StringOrSymbol to_property_key(GlobalObject&) const;
     i32 to_i32(GlobalObject& global_object) const