diff -r 1c6b099ead89 src/undo.c
--- a/src/undo.c	Sun May 27 00:37:51 2012 +0200
+++ b/src/undo.c	Thu May 31 20:06:14 2012 +0200
@@ -1535,6 +1535,7 @@
 	/* For systems that support ACL: get the ACL from the original file. */
 	acl = mch_get_acl(buf->b_ffname);
 	mch_set_acl(file_name, acl);
+	mch_free_acl(acl);
     }
 #endif