diff --git a/lib/src/ca.c b/lib/src/ca.c
index 9c38caa..72f2a31 100644
--- a/lib/src/ca.c
+++ b/lib/src/ca.c
@@ -631,6 +631,9 @@ static int init_ca(struct dddvb *dd, int a, int f, int fd)
 	struct dddvb_ca *ca;
 	char fname[80];
 
+	if (dd->dvbca_num >= DDDVB_MAX_DVB_CA)
+		return -1;
+
 	ca = &dd->dvbca[dd->dvbca_num];
 	ca->dd = dd;
 	ca->anum = a;
diff --git a/lib/src/dvb.c b/lib/src/dvb.c
index b639078..a7b9586 100644
--- a/lib/src/dvb.c
+++ b/lib/src/dvb.c
@@ -798,6 +798,9 @@ static int dddvb_fe_init(struct dddvb *dd, int a, int f, int fd)
 	int r;
 	uint32_t i, ds;
 
+	if (dd->dvbfe_num >= DDDVB_MAX_DVB_FE)
+		return -1;
+
 	fe = &dd->dvbfe[dd->dvbfe_num];
 
 	r = snprintf(fe->name, sizeof(fe->name), "/dev/dvb/adapter%d/frontend%d", a, f);