diff --git a/NEWS b/NEWS
index c3b8df9358f1ac26e6bd8cf91aa94395d38d21e2..e82caf86fa85a445aaa0fcfc896e261df2e326fc 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ documents those changes that are of interest to users and admins.
 * Changes in SLURM 1.2.5
 ========================
  -- Fix nodelist truncation in "scontrol show jobs" output
+ -- In mpi/mpichgm, fix potential problem formatting GMPI_PORT, from
+    Ernest Artiaga, BSC.
 
 * Changes in SLURM 1.2.4
 ========================
diff --git a/src/plugins/mpi/mpichgm/mpichgm.c b/src/plugins/mpi/mpichgm/mpichgm.c
index 27083df09853780241d413ff7b809375a79b2875..b78c99f1d7186b95dc996bad5a269126d1143dfa 100644
--- a/src/plugins/mpi/mpichgm/mpichgm.c
+++ b/src/plugins/mpi/mpichgm/mpichgm.c
@@ -366,7 +366,7 @@ gmpi_thr_create(const mpi_plugin_client_info_t *job, char ***env)
 	}
 	slurm_attr_destroy(&attr);
 
-	env_array_overwrite_fmt(env, "GMPI_PORT",  "%u", port);
+	env_array_overwrite_fmt(env, "GMPI_PORT",  "%hu", port);
 	env_array_overwrite_fmt(env, "GMPI_MAGIC", "%u", job->jobid);
 	env_array_overwrite_fmt(env, "GMPI_NP",    "%d", 
 				job->step_layout->task_cnt);