diff --git a/ggml-backend.c b/ggml-backend.c
index 778f58083..9ee81b766 100644
--- a/ggml-backend.c
+++ b/ggml-backend.c
@@ -475,7 +475,7 @@ ggml_backend_buffer_t ggml_backend_reg_alloc_buffer(size_t i, size_t size) {
 
 // backend CPU
 
-static const size_t TENSOR_ALIGNMENT = 64; // should be enough for AVX 512
+static const size_t TENSOR_ALIGNMENT = 32; // required for mmap as gguf only guarantees 32-byte alignment
 
 GGML_CALL static const char * ggml_backend_cpu_buffer_name(ggml_backend_buffer_t buffer) {
     return "CPU";
@@ -818,6 +818,7 @@ void ggml_backend_cpu_set_abort_callback(ggml_backend_t backend_cpu, ggml_abort_
 }
 
 GGML_CALL ggml_backend_buffer_t ggml_backend_cpu_buffer_from_ptr(void * ptr, size_t size) {
+    GGML_ASSERT((uintptr_t)ptr % TENSOR_ALIGNMENT == 0 && "buffer pointer must be aligned");
     return ggml_backend_buffer_init(ggml_backend_cpu_buffer_type(), cpu_backend_buffer_i_from_ptr, ptr, size);
 }