--- /dev/null
+diff --git a/scapy/layers/inet6.py b/scapy/layers/inet6.py
+index b58978f4..c4a3084d 100644
+--- a/scapy/layers/inet6.py
++++ b/scapy/layers/inet6.py
+@@ -1073,6 +1073,7 @@ def defragment6(packets):
+ q = res[0]
+ nh = q[IPv6ExtHdrFragment].nh
+ q[IPv6ExtHdrFragment].underlayer.nh = nh
++ q[IPv6ExtHdrFragment].underlayer.plen = len(fragmentable)
+ del q[IPv6ExtHdrFragment].underlayer.payload
+ q /= conf.raw_layer(load=fragmentable)
+