charon/sa/ike_sa.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 IKE_SA_INIT request that triggers “an incomplete state,” followed by a CREATE_CHILD_SA request.
download.strongswan.org/CHANGES4.txt
download.strongswan.org/patches/03_invalid_ike_state_patch/strongswan-4.x.x_invalid_ike_state.patch
download.strongswan.org/patches/03_invalid_ike_state_patch/strongswan-4.x.x_invalid_ike_state.readme
lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html
secunia.com/advisories/35296
secunia.com/advisories/35685
secunia.com/advisories/36922
www.debian.org/security/2009/dsa-1899
www.securityfocus.com/bid/35178
lists.strongswan.org/pipermail/users/2009-May/003457.html