diff --git a/cpp/include/raft/stats/detail/sum.cuh b/cpp/include/raft/stats/detail/sum.cuh
index 1d727f8b77..bb45eb50f4 100644
--- a/cpp/include/raft/stats/detail/sum.cuh
+++ b/cpp/include/raft/stats/detail/sum.cuh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2021-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -43,7 +43,7 @@ RAFT_KERNEL sumKernelRowMajor(Type* mu, const Type* data, IdxType D, IdxType N)
   __syncthreads();
   raft::myAtomicAdd(smu + thisColId, thread_data);
   __syncthreads();
-  if (threadIdx.x < ColsPerBlk) raft::myAtomicAdd(mu + colId, smu[thisColId]);
+  if (threadIdx.x < ColsPerBlk && colId < D) raft::myAtomicAdd(mu + colId, smu[thisColId]);
 }
 
 template <typename Type, typename IdxType, int TPB>
diff --git a/cpp/test/stats/sum.cu b/cpp/test/stats/sum.cu
index 040b662c42..290c53a563 100644
--- a/cpp/test/stats/sum.cu
+++ b/cpp/test/stats/sum.cu
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018-2023, NVIDIA CORPORATION.
+ * Copyright (c) 2018-2024, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -81,8 +81,8 @@ class SumTest : public ::testing::TestWithParam<SumInputs<T>> {
   rmm::device_uvector<T> data, sum_act;
 };
 
-const std::vector<SumInputs<float>> inputsf = {{0.05f, 1024, 32, 1234ULL},
-                                               {0.05f, 1024, 256, 1234ULL}};
+const std::vector<SumInputs<float>> inputsf = {
+  {0.05f, 4, 5, 1234ULL}, {0.05f, 1024, 32, 1234ULL}, {0.05f, 1024, 256, 1234ULL}};
 
 const std::vector<SumInputs<double>> inputsd = {{0.05, 1024, 32, 1234ULL},
                                                 {0.05, 1024, 256, 1234ULL}};