The Libreswan Project has found a vulnerability in the processing of IKEv1 informational exchange packets which are encrypted and integrity protected using the established IKE SA encryption and integrity keys, but as a receiver, the integrity check value was not verified. This issue affects versions before 3.29.

In Libreswan 3.27 an assertion failure can lead to a pluto IKE daemon restart. An attacker can trigger a NULL pointer dereference by initiating an IKEv2 IKE_SA_INIT exchange, followed by a bogus INFORMATIONAL exchange instead of the normallly expected IKE_AUTH exchange. This affects send_v2N_spi_response_from_state() in programs/pluto/ikev2_send.c that will then trigger a NULL pointer dereference leading to a restart of libreswan.

libreswan before 3.18 allows remote attackers to cause a denial of service (NULL pointer dereference and pluto daemon restart).

programs/pluto/ikev1.c in libreswan before 3.17 retransmits in initial-responder states, which allows remote attackers to cause a denial of service (traffic amplification) via a spoofed UDP packet. NOTE: the original behavior complies with the IKEv1 protocol, but has a required security update from the libreswan vendor; as of 2016-06-10, it is expected that several other IKEv1 implementations will have vendor-required security updates, with separate CVE IDs assigned to each.

Libreswan 3.16 might allow remote attackers to cause a denial of service (daemon restart) via an IKEv2 aes_xcbc transform.

The pluto IKE daemon in libreswan before 3.15 and Openswan before 2.6.45, when built with NSS, allows remote attackers to cause a denial of service (assertion failure and daemon restart) via a zero DH g^x value in a KE payload in a IKE packet.

libreswan 3.9 through 3.12 allows remote attackers to cause a denial of service (daemon restart) via an IKEv1 packet with (1) unassigned bits set in the IPSEC DOI value or (2) the next payload value set to ISAKMP_NEXT_SAK.

Libreswan 3.7 and earlier allows remote attackers to cause a denial of service (NULL pointer dereference and IKE daemon restart) via IKEv2 packets that lack expected payloads.

The ikev2parent_inI1outR1 function in pluto/ikev2_parent.c in libreswan before 3.7 allows remote attackers to cause a denial of service (restart) via an IKEv2 I1 notification without a KE payload.

Race condition in the libreswan.spec files for Red Hat Enterprise Linux (RHEL) and Fedora packages in libreswan 3.6 has unspecified impact and attack vectors, involving the /var/tmp/libreswan-nss-pwd temporary file.