diff --git a/libnetutil/netutil.cc b/libnetutil/netutil.cc
index 8ab28dc61..d5af1d284 100644
--- a/libnetutil/netutil.cc
+++ b/libnetutil/netutil.cc
@@ -3024,15 +3024,21 @@ icmpbad:
         srchost, dsthost, icmptype, icmpinfo, icmpfields, ipinfo);
     }
 
-    /* UNKNOWN PROTOCOL **********************************************************/
   } else if (hdr.proto == IPPROTO_ICMPV6) {
-    const struct icmpv6_hdr *icmpv6;
+    if (datalen > sizeof(struct icmpv6_hdr)) {
+      const struct icmpv6_hdr *icmpv6;
 
-    icmpv6 = (struct icmpv6_hdr *) data;
-    Snprintf(protoinfo, sizeof(protoinfo), "ICMPv6 (%d) %s > %s (type=%d/code=%d) %s",
-      hdr.proto, srchost, dsthost,
-      icmpv6->icmpv6_type, icmpv6->icmpv6_code, ipinfo);
+      icmpv6 = (struct icmpv6_hdr *) data;
+      Snprintf(protoinfo, sizeof(protoinfo), "ICMPv6 (%d) %s > %s (type=%d/code=%d) %s",
+          hdr.proto, srchost, dsthost,
+          icmpv6->icmpv6_type, icmpv6->icmpv6_code, ipinfo);
+    }
+    else {
+      Snprintf(protoinfo, sizeof(protoinfo), "ICMPv6 (%d) %s > %s (type=?/code=?) %s",
+          hdr.proto, srchost, dsthost, ipinfo);
+    }
   } else {
+    /* UNKNOWN PROTOCOL **********************************************************/
     const char *hdrstr;
 
     hdrstr = nexthdrtoa(hdr.proto, 1);
diff --git a/scan_engine_raw.cc b/scan_engine_raw.cc
index 11c439302..e3bfdf255 100644
--- a/scan_engine_raw.cc
+++ b/scan_engine_raw.cc
@@ -181,20 +181,21 @@ void UltraProbe::setIP(u8 *ippacket, u32 len, const probespec *pspec) {
   }
 
   if (hdr == IPPROTO_TCP) {
-    assert(len >= 20);
+    assert(len >= sizeof(struct tcp_hdr));
     tcp = (struct tcp_hdr *) data;
     probes.IP.pd.tcp.sport = ntohs(tcp->th_sport);
     probes.IP.pd.tcp.seq = ntohl(tcp->th_seq);
   } else if (hdr == IPPROTO_UDP) {
-    assert(len >= 8);
+    assert(len >= sizeof(struct udp_hdr));
     udp = (struct udp_hdr *) data;
     probes.IP.pd.udp.sport = ntohs(udp->uh_sport);
   } else if (hdr == IPPROTO_SCTP) {
-    assert(len >= 12);
+    assert(len >= sizeof(struct sctp_hdr));
     sctp = (struct sctp_hdr *) data;
     probes.IP.pd.sctp.sport = ntohs(sctp->sh_sport);
     probes.IP.pd.sctp.vtag = ntohl(sctp->sh_vtag);
-  } else if (hdr == IPPROTO_ICMP || hdr == IPPROTO_ICMPV6) {
+  } else if ((ip->ip_v == 4 && hdr == IPPROTO_ICMP) || (ip->ip_v == 6 && hdr == IPPROTO_ICMPV6)) {
+    assert(len >= sizeof(struct ppkt));
     icmp = (struct ppkt *) data;
     probes.IP.pd.icmp.ident = ntohs(icmp->id);
   }