diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -372,6 +372,7 @@
 				int, u_int16_t);
 static int		 pf_check_proto_cksum(struct mbuf *, int, int,
 			    u_int8_t, sa_family_t);
+static int		 pf_walk_header(struct pf_pdesc *, struct ip *, u_short *);
 static int		 pf_walk_option6(struct pf_pdesc *, struct ip6_hdr *,
 			    int, int, u_short *);
 static int		 pf_walk_header6(struct pf_pdesc *, struct ip6_hdr *,
@@ -7911,9 +7912,10 @@
 			}
 
 			/* offset of protocol header that follows h2 */
-			pd2.off = ipoff2 + (h2.ip_hl << 2);
+			pd2.off = ipoff2;
+			if (pf_walk_header(&pd2, &h2, reason) != PF_PASS)
+				return (PF_DROP);
 
-			pd2.proto = h2.ip_p;
 			pd2.tot_len = ntohs(h2.ip_len);
 			pd2.src = (struct pf_addr *)&h2.ip_src;
 			pd2.dst = (struct pf_addr *)&h2.ip_dst;
@@ -9689,6 +9691,44 @@
 	return (0);
 }
 
+static int
+pf_walk_header(struct pf_pdesc *pd, struct ip *h, u_short *reason)
+{
+	struct ip6_ext	 ext;
+	u_int32_t	 hlen, end;
+
+	hlen = h->ip_hl << 2;
+	if (hlen < sizeof(struct ip) || hlen > ntohs(h->ip_len)) {
+		REASON_SET(reason, PFRES_SHORT);
+		return (PF_DROP);
+	}
+	end = pd->off + ntohs(h->ip_len);
+	pd->off += hlen;
+	pd->proto = h->ip_p;
+	/* stop walking over non initial fragments */
+	if ((h->ip_off & htons(IP_OFFMASK)) != 0)
+		return (PF_PASS);
+	for (;;) {
+		switch (pd->proto) {
+		case IPPROTO_AH:
+			/* fragments may be short */
+			if ((h->ip_off & htons(IP_MF | IP_OFFMASK)) != 0 &&
+			    end < pd->off + sizeof(ext))
+				return (PF_PASS);
+			if (!pf_pull_hdr(pd->m, pd->off, &ext, sizeof(ext),
+				NULL, reason, AF_INET)) {
+				DPFPRINTF(PF_DEBUG_MISC, ("IP short exthdr"));
+				return (PF_DROP);
+			}
+			pd->off += (ext.ip6e_len + 2) * 4;
+			pd->proto = ext.ip6e_nxt;
+			break;
+		default:
+			return (PF_PASS);
+		}
+	}
+}
+
 #ifdef INET6
 static int
 pf_walk_option6(struct pf_pdesc *pd, struct ip6_hdr *h, int off, int end,
@@ -9936,18 +9976,22 @@
 		*m0 = pd->m;
 
 		h = mtod(pd->m, struct ip *);
-		pd->off = h->ip_hl << 2;
-		if (pd->off < (int)sizeof(*h)) {
+		if (pd->m->m_pkthdr.len < ntohs(h->ip_len)) {
 			*action = PF_DROP;
 			REASON_SET(reason, PFRES_SHORT);
 			return (-1);
 		}
+
+		if (pf_walk_header(pd, h, reason) != PF_PASS) {
+			*action = PF_DROP;
+			return (-1);
+		}
+
 		pd->src = (struct pf_addr *)&h->ip_src;
 		pd->dst = (struct pf_addr *)&h->ip_dst;
 		PF_ACPY(&pd->osrc, pd->src, af);
 		PF_ACPY(&pd->odst, pd->dst, af);
 		pd->ip_sum = &h->ip_sum;
-		pd->virtual_proto = pd->proto = h->ip_p;
 		pd->tos = h->ip_tos & ~IPTOS_ECN_MASK;
 		pd->ttl = h->ip_ttl;
 		pd->tot_len = ntohs(h->ip_len);
@@ -9957,8 +10001,8 @@
 		if (h->ip_hl > 5)	/* has options */
 			pd->badopts++;
 
-		if (h->ip_off & htons(IP_MF | IP_OFFMASK))
-			pd->virtual_proto = PF_VPROTO_FRAGMENT;
+		pd->virtual_proto = (h->ip_off & htons(IP_MF | IP_OFFMASK)) ?
+		    PF_VPROTO_FRAGMENT : pd->proto;
 
 		break;
 	}
@@ -9978,7 +10022,7 @@
 		}
 
 		h = mtod(pd->m, struct ip6_hdr *);
-		pd->off = 0;
+
 		if (pf_walk_header6(pd, h, reason) != PF_PASS) {
 			*action = PF_DROP;
 			return (-1);
@@ -9993,11 +10037,10 @@
 		pd->tos = IPV6_DSCP(h);
 		pd->ttl = h->ip6_hlim;
 		pd->tot_len = ntohs(h->ip6_plen) + sizeof(struct ip6_hdr);
-		pd->virtual_proto = pd->proto = h->ip6_nxt;
 		pd->act.rtableid = -1;
 
-		if (pd->fragoff != 0)
-			pd->virtual_proto = PF_VPROTO_FRAGMENT;
+		pd->virtual_proto = (pd->fragoff != 0) ?
+		    PF_VPROTO_FRAGMENT : pd->proto;
 
 		/*
 		 * we do not support jumbogram.  if we keep going, zero ip6_plen