diff --git a/src/core/ipv4/ip_frag.c b/src/core/ipv4/ip_frag.c
index 8bf8141f..86901156 100644
--- a/src/core/ipv4/ip_frag.c
+++ b/src/core/ipv4/ip_frag.c
@@ -595,7 +595,7 @@ ip_reass(struct pbuf *p)
     }
 
     /* find the previous entry in the linked list */
-    for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr = ipr->next) {
+    for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
       if (ipr_prev->next == ipr) {
         break;
       }
diff --git a/src/core/ipv6/ip6_frag.c b/src/core/ipv6/ip6_frag.c
index 77fdde5a..abb32733 100644
--- a/src/core/ipv6/ip6_frag.c
+++ b/src/core/ipv6/ip6_frag.c
@@ -292,7 +292,7 @@ ip6_reass(struct pbuf *p)
       ipr = (struct ip6_reassdata *)memp_malloc(MEMP_IP6_REASSDATA);
       if (ipr != NULL) {
         /* re-search ipr_prev since it might have been removed */
-        for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr = ipr->next) {
+        for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
           if (ipr_prev->next == ipr) {
             break;
           }
@@ -331,7 +331,7 @@ ip6_reass(struct pbuf *p)
     ip6_reass_remove_oldest_datagram(ipr, clen);
     if ((ip6_reass_pbufcount + clen) <= IP_REASS_MAX_PBUFS) {
       /* re-search ipr_prev since it might have been removed */
-      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr = ipr->next) {
+      for (ipr_prev = reassdatagrams; ipr_prev != NULL; ipr_prev = ipr_prev->next) {
         if (ipr_prev->next == ipr) {
           break;
         }