diff --git a/src/common/md5.cc b/src/common/md5.cc
index a0d9a1bd..4f1ac8ca 100644
--- a/src/common/md5.cc
+++ b/src/common/md5.cc
@@ -138,8 +138,8 @@ void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
   byteReverse(ctx->in, 14);
 
   /* Append length in bits and transform */
-  ((u32 *) ctx->in)[14] = ctx->bits[0];
-  ((u32 *) ctx->in)[15] = ctx->bits[1];
+  memcpy(&ctx->in[14], &ctx->bits[0], sizeof(u32));
+  memcpy(&ctx->in[15], &ctx->bits[1], sizeof(u32));
 
   MD5Transform(ctx->buf, (u32 *) ctx->in);
   byteReverse((unsigned char *) ctx->buf, 4);