diff --git a/cpu/native/periph/random.c b/cpu/native/periph/random.c
index 25e597a95da62839e1ca3dc79451e2a71b784796..9fe1dcae10969b8dea0ae8af06e588c214dda947 100644
--- a/cpu/native/periph/random.c
+++ b/cpu/native/periph/random.c
@@ -92,7 +92,6 @@ int random_read(char *buf, unsigned int num)
             num = _native_rng_read_det(buf, num);
             break;
         default:
-            num = 0;
             err(EXIT_FAILURE, "random_read: _native_rng_mode is in invalid state %i\n",
                    _native_rng_mode);
             break;
diff --git a/sys/net/link_layer/ng_netdev_eth/ng_netdev_eth.c b/sys/net/link_layer/ng_netdev_eth/ng_netdev_eth.c
index db08d7e68e11265fc5c3947299ac5a8b5ab5bad2..889f0111b92d1d079d6519cad07a7c4a34c58de3 100644
--- a/sys/net/link_layer/ng_netdev_eth/ng_netdev_eth.c
+++ b/sys/net/link_layer/ng_netdev_eth/ng_netdev_eth.c
@@ -364,7 +364,9 @@ static inline void _addr_set_multicast(uint8_t *dst, ng_pktsnip_t *payload)
         case NG_NETTYPE_IPV6:
             dst[0] = 0x33;
             dst[1] = 0x33;
-            memcpy(dst + 2, ((uint8_t *)payload->data) + _IPV6_DST_OFFSET, 4);
+            if ((payload != NULL) && (payload->data != NULL)) {
+                memcpy(dst + 2, ((uint8_t *)payload->data) + _IPV6_DST_OFFSET, 4);
+            }
             /* TODO change to proper types when ng_ipv6_hdr_t got merged */
             break;
 #endif
diff --git a/sys/net/network_layer/ng_icmpv6/ng_icmpv6.c b/sys/net/network_layer/ng_icmpv6/ng_icmpv6.c
index a27734fc007e33a9ae3d538898e199be59444324..95560763239c3156ec67c1e1450aed32f89e6e00 100644
--- a/sys/net/network_layer/ng_icmpv6/ng_icmpv6.c
+++ b/sys/net/network_layer/ng_icmpv6/ng_icmpv6.c
@@ -62,10 +62,14 @@ void ng_icmpv6_demux(kernel_pid_t iface, ng_pktsnip_t *pkt)
 
     LL_SEARCH_SCALAR(pkt, icmpv6, type, NG_NETTYPE_ICMPV6);
 
+    assert(icmpv6 != NULL);
+
     /* there can be extension headers between IPv6 and ICMPv6 header so we have
      * to search it */
     LL_SEARCH_SCALAR(icmpv6, ipv6, type, NG_NETTYPE_IPV6);
 
+    assert(ipv6 != NULL);
+
     hdr = (ng_icmpv6_hdr_t *)icmpv6->data;
 
     if (_calc_csum(icmpv6, ipv6, pkt)) {
diff --git a/sys/net/network_layer/ng_ipv6/ng_ipv6.c b/sys/net/network_layer/ng_ipv6/ng_ipv6.c
index 02f6f96a4fe5dfe4cb21917262ff1c12ef23a5e0..328d7f5ebb39b0426d5448d9dbcba97c111e74e3 100644
--- a/sys/net/network_layer/ng_ipv6/ng_ipv6.c
+++ b/sys/net/network_layer/ng_ipv6/ng_ipv6.c
@@ -593,6 +593,8 @@ static void _receive(ng_pktsnip_t *pkt)
     ng_pktsnip_t *ipv6, *netif;
     ng_ipv6_hdr_t *hdr;
 
+    assert(pkt != NULL);
+
     LL_SEARCH_SCALAR(pkt, netif, type, NG_NETTYPE_NETIF);
 
     if (netif != NULL) {
diff --git a/sys/net/network_layer/ng_sixlowpan/ng_sixlowpan.c b/sys/net/network_layer/ng_sixlowpan/ng_sixlowpan.c
index 809a66431015531543ebee66d7227b86af52b6e2..f2c60f199e3b75b3ca808f3b208030ee36a17f35 100644
--- a/sys/net/network_layer/ng_sixlowpan/ng_sixlowpan.c
+++ b/sys/net/network_layer/ng_sixlowpan/ng_sixlowpan.c
@@ -237,6 +237,9 @@ static void _send(ng_pktsnip_t *pkt)
         payload_len++;
     }
 #else
+    /* suppress clang-analyzer report about iface being not read */
+    (void) iface;
+
     DEBUG("6lo: Send uncompressed\n");
 
     sixlowpan = ng_pktbuf_add(NULL, NULL, sizeof(uint8_t), NG_NETTYPE_SIXLOWPAN);
diff --git a/sys/net/transport_layer/ng_udp/ng_udp.c b/sys/net/transport_layer/ng_udp/ng_udp.c
index 6787d9bd0c7bb4bc192722c2058194bd1a27e914..4e3f0ce27dae968abeb123c12504100b5a229584 100644
--- a/sys/net/transport_layer/ng_udp/ng_udp.c
+++ b/sys/net/transport_layer/ng_udp/ng_udp.c
@@ -120,6 +120,8 @@ static void _receive(ng_pktsnip_t *pkt)
 
     LL_SEARCH_SCALAR(pkt, ipv6, type, NG_NETTYPE_IPV6);
 
+    assert(ipv6 != NULL);
+
     /* validate checksum */
     if (_calc_csum(udp, ipv6, pkt)) {
         DEBUG("udp: received packet with invalid checksum, dropping it\n");
@@ -144,6 +146,9 @@ static void _send(ng_pktsnip_t *pkt)
 
     /* get udp snip and hdr */
     LL_SEARCH_SCALAR(pkt, udp_snip, type, NG_NETTYPE_UDP);
+
+    assert(udp_snip != NULL);
+
     udp_snip = ng_pktbuf_start_write(udp_snip);
     if (udp_snip == NULL) {
         DEBUG("udp: cannot send packet: unable to allocate packet\n");