diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index f83289b..4258364 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -606,8 +606,11 @@
 	}
 }
 
-void bsc_parse_reg(void *ctx, regex_t *reg, char **imsi, int argc, const char **argv)
+int bsc_parse_reg(void *ctx, regex_t *reg, char **imsi, int argc, const char **argv)
 {
+	int ret;
+
+	ret = 0;
 	if (*imsi) {
 		talloc_free(*imsi);
 		*imsi = NULL;
@@ -616,8 +619,16 @@
 
 	if (argc > 0) {
 		*imsi = talloc_strdup(ctx, argv[0]);
-		regcomp(reg, argv[0], 0);
+		ret = regcomp(reg, argv[0], 0);
+
+		/* handle compilation failures */
+		if (ret != 0) {
+			talloc_free(*imsi);
+			*imsi = NULL;
+		}
 	}
+
+	return ret;
 }
 
 static const char *con_types [] = {
diff --git a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
index 3158f34..3a5068e 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_vty.c
@@ -467,7 +467,8 @@
       "Set the USSD query to match with the ussd-list-name\n"
       "The query to match")
 {
-	bsc_parse_reg(_nat, &_nat->ussd_query_re, &_nat->ussd_query, argc, argv);
+	if (bsc_parse_reg(_nat, &_nat->ussd_query_re, &_nat->ussd_query, argc, argv) != 0)
+		return CMD_WARNING;
 	return CMD_SUCCESS;
 }
 
@@ -580,7 +581,8 @@
 	if (!entry)
 		return CMD_WARNING;
 
-	bsc_parse_reg(acc, &entry->imsi_allow_re, &entry->imsi_allow, argc - 1, &argv[1]);
+	if (bsc_parse_reg(acc, &entry->imsi_allow_re, &entry->imsi_allow, argc - 1, &argv[1]) != 0)
+		return CMD_WARNING;
 	return CMD_SUCCESS;
 }
 
@@ -602,7 +604,8 @@
 	if (!entry)
 		return CMD_WARNING;
 
-	bsc_parse_reg(acc, &entry->imsi_deny_re, &entry->imsi_deny, argc - 1, &argv[1]);
+	if (bsc_parse_reg(acc, &entry->imsi_deny_re, &entry->imsi_deny, argc - 1, &argv[1]) != 0)
+		return CMD_WARNING;
 	return CMD_SUCCESS;
 }
 
@@ -710,7 +713,8 @@
 	char *str = NULL;
 
 	memset(&reg, 0, sizeof(reg));
-	bsc_parse_reg(_nat, &reg, &str, 1, argv);
+	if (bsc_parse_reg(_nat, &reg, &str, 1, argv) != 0)
+		return CMD_WARNING;
 
 	vty_out(vty, "String matches allow pattern: %d%s",
 		regexec(&reg, argv[1], 0, NULL, 0) == 0, VTY_NEWLINE);