diff --git a/src/exec.c b/src/exec.c
index a9d8ce0..b806ad5 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -217,6 +217,9 @@
 		/* close all file descriptors above stdio */
 		osmo_close_all_fds_above(2);
 
+		/* man execle: "an array of pointers *must* be terminated by a null pointer" */
+		new_env[0] = NULL;
+
 		/* build the new environment */
 		if (env_whitelist)
 			osmo_environment_filter(new_env, ARRAY_SIZE(new_env), environ, env_whitelist);