diff --git a/src/http/httpd.c b/src/http/httpd.c
index cd3ca63..429a6d8 100644
--- a/src/http/httpd.c
+++ b/src/http/httpd.c
@@ -265,7 +265,7 @@ int http_url_encode(char *buf, size_t len, size_t max_len) {
     char *p = buf;
     char *q = NULL;
     while (p < buf + len) {
-        q = strchr(p, ' ');
+        q = memchr(p, ' ', len - (size_t)(p - buf));
         if (!q) {
             break;
         }
diff --git a/src/wolfip.c b/src/wolfip.c
index c08ed1b..647a8e7 100644
--- a/src/wolfip.c
+++ b/src/wolfip.c
@@ -1230,8 +1230,16 @@ static void udp_try_recv(struct wolfIP *s, unsigned int if_idx, struct wolfIP_ud
 {
     struct ipconf *conf = wolfIP_ipconf_at(s, if_idx);
     int i;
-    ip4 local_ip = conf ? conf->ip : IPADDR_ANY;
-    ip4 dst_ip = ee32(udp->ip.dst);
+    ip4 local_ip;
+    ip4 dst_ip;
+
+    /* validate minimum UDP datagram length */
+    if (frame_len < sizeof(struct wolfIP_udp_datagram))
+        return;
+
+    local_ip = conf ? conf->ip : IPADDR_ANY;
+    dst_ip = ee32(udp->ip.dst);
+
     if (wolfIP_filter_notify_udp(WOLFIP_FILT_RECEIVING, s, if_idx, udp, frame_len) != 0)
         return;
     for (i = 0; i < MAX_UDPSOCKETS; i++) {
@@ -1739,6 +1747,11 @@ static void tcp_ack(struct tsocket *t, const struct wolfIP_tcp_seg *tcp)
 static void tcp_input(struct wolfIP *S, unsigned int if_idx, struct wolfIP_tcp_seg *tcp, uint32_t frame_len)
 {
     int i;
+
+    /* validate minimum TCP segment length */
+    if (frame_len < sizeof(struct wolfIP_tcp_seg))
+        return;
+
     if (wolfIP_filter_notify_tcp(WOLFIP_FILT_RECEIVING, S, if_idx, tcp, frame_len) != 0)
         return;
     for (i = 0; i < MAX_TCPSOCKETS; i++) {
@@ -2783,6 +2796,12 @@ static void icmp_input(struct wolfIP *s, unsigned int if_idx, struct wolfIP_ip_p
     struct wolfIP_icmp_packet *icmp = (struct wolfIP_icmp_packet *)ip;
     uint32_t tmp;
     struct wolfIP_ll_dev *ll = wolfIP_ll_at(s, if_idx);
+
+    /* validate minimum ICMP packet length */
+    if (len < sizeof(struct wolfIP_icmp_packet))
+        return;
+
+
     if (wolfIP_filter_notify_icmp(WOLFIP_FILT_RECEIVING, s, if_idx, icmp, len) != 0)
         return;
     if (icmp->type == ICMP_ECHO_REPLY) {
@@ -3255,6 +3274,11 @@ static void arp_recv(struct wolfIP *s, unsigned int if_idx, void *buf, int len)
     struct wolfIP_ll_dev *ll = wolfIP_ll_at(s, if_idx);
     struct ipconf *conf;
 
+
+    /* validate minimum ARP packet length */
+    if (len < (int)sizeof(struct arp_packet))
+        return;
+
     if (!ll)
         return;
     conf = wolfIP_ipconf_at(s, if_idx);
@@ -3365,6 +3389,10 @@ static inline void ip_recv(struct wolfIP *s, unsigned int if_idx, struct wolfIP_
 #if WOLFIP_ENABLE_FORWARDING
     unsigned int i;
 #endif
+    /* validate minimum packet length
+     * (ethernet header+ ip header, with no options) */
+    if (len < sizeof(struct wolfIP_ip_packet))
+        return;
 #if WOLFIP_ENABLE_LOOPBACK
     if (!wolfIP_is_loopback_if(if_idx)) {
         ip4 dest = ee32(ip->dst);