racoon/isakmp_frag.c in ipsec-tools before 0.7.2 allows remote attackers to cause a denial of service via crafted fragmented packets without a payload, which triggers a NULL pointer dereference . Updated packages are available that brings ipsec-tools to version 0.7.2 for Mandriva Linux 2008.1/2009.0/2009.1 which provides numerous bugfixes over the previous 0.7.1 version, and also corrects this issue. ipsec-tools for Mandriva Linux Corporate Server 4 has been patched to address this issue. Additionally the flex package required for building ipsec-tools has been fixed due to ipsec-tools build problems and is also available with this update.