diff --git a/src/protocol/file/cgi.c b/src/protocol/file/cgi.c
index 1bbd5168..9403dae7 100644
--- a/src/protocol/file/cgi.c
+++ b/src/protocol/file/cgi.c
@@ -347,7 +347,7 @@ execute_cgi(struct connection *conn)
 		close_all_non_term_fd();
 
 		last_slash[-1] = 0; set_cwd(script); last_slash[-1] = '/';
-		if (execl(script, script, NULL)) {
+		if (execl(script, script, (char *) NULL)) {
 			_exit(3);
 		}