diff --git a/src/core/mem.c b/src/core/mem.c
index ffc0c292..9ca9e3c4 100644
--- a/src/core/mem.c
+++ b/src/core/mem.c
@@ -674,7 +674,7 @@ void *mem_calloc(mem_size_t count, mem_size_t size)
   p = mem_malloc(count * size);
   if (p) {
     /* zero the memory */
-    memset(p, 0, count * size);
+    memset(p, 0, (size_t)count * (size_t)size);
   }
   return p;
 }