charon/sa/tasks/child_create.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 IKE_AUTH request without a (1) TSi or (2) TSr traffic selector.
strongSwan 4.2.6 and earlier allows remote attackers to cause a denial of service (daemon crash) via an IKE_SA_INIT message with a large number of NULL values in a Key Exchange payload, which triggers a NULL pointer dereference for the return value of the mpz_export function in the GNU Multiprecision Library (GMP).
FreeS/WAN 1.x and 2.x, and other related products including superfreeswan 1.x, openswan 1.x before 1.0.6, openswan 2.x before 2.1.4, and strongSwan before 2.1.3, allows remote attackers to authenticate using spoofed PKCS#7 certificates in which a self-signed certificate identifies an alternate Certificate Authority (CA) and spoofed issuer and subject.