diff --git a/src/supplicant-manager/nm-supplicant-config.c b/src/supplicant-manager/nm-supplicant-config.c
index b676e068b..721770ef1 100644
--- a/src/supplicant-manager/nm-supplicant-config.c
+++ b/src/supplicant-manager/nm-supplicant-config.c
@@ -128,7 +128,7 @@ nm_supplicant_config_add_option (NMSupplicantConfig *self,
 		return FALSE;
 	}
 
-	opt->value = g_malloc0 (sizeof (char) * len);
+	opt->value = g_malloc0 ((sizeof (char) * len) + 1);
 	if (opt->value == NULL) {
 		nm_debug ("Couldn't allocate memory for new config option value.");
 		g_slice_free (ConfigOption, opt);