diff --git a/ggml/src/ggml-cuda/mmq.cu b/ggml/src/ggml-cuda/mmq.cu
index 707437ea3e52..6af7a27e194f 100644
--- a/ggml/src/ggml-cuda/mmq.cu
+++ b/ggml/src/ggml-cuda/mmq.cu
@@ -203,7 +203,7 @@ void ggml_cuda_mul_mat_q(
     }
 
     const size_t nbytes_src1_q8_1 = ne12*n_expert_used*ne10_padded * y_block_size/y_values_per_block +
-        ggml_cuda_mmq_get_J_max(src0->type, fallback, cc, ne11) * sizeof(block_q8_1_mmq);
+        ggml_cuda_mmq_get_J_max(src0->type, fallback, cc, ne12*n_expert_used) * sizeof(block_q8_1_mmq);
     ggml_cuda_pool_alloc<char> src1_q8_1(ctx.pool(), nbytes_src1_q8_1);
     ggml_cuda_pool_alloc<float> src1_scale(ctx.pool());
     if (src0->type == GGML_TYPE_NVFP4 && use_native_fp4) {