The pluto IKE daemon in Openswan and Strongswan IPsec 2.6 before 2.6.21 and 2.4 before 2.4.14, and Strongswan 4.2 before 4.2.14 and 2.8 before 2.8.9, allows remote attackers to cause a denial of service (daemon crash and restart) via a crafted (1) RUTHERE or (2) RUTHEREACK Dead Peer Detection (DPD) IPsec IKE Notification message that triggers a NULL pointer dereference related to inconsistent ISAKMP state and the lack of a phase2 state association in DPD.

charon/sa/tasks/childcreate.c in the charon daemon in strongSWAN before 4.3.1 switches the NULL checks for TSi and TSr payloads, which allows remote attackers to cause a denial of service via an IKEAUTH request without a (1) TSi or (2) TSr traffic selector.

charon/sa/ikesa.c in the charon daemon in strongSWAN before 4.3.1 allows remote attackers to cause a denial of service (NULL pointer dereference and crash) via an invalid IKESAINIT request that triggers "an incomplete state," followed by a CREATECHILDSA request.