The Libreswan Project was notified of an issue causing libreswan to restart when using IKEv1 without specifying an esp= line. When the peer requests AES-GMAC, libreswan's default proposal handler causes an assertion failure and crashes and restarts. IKEv2 connections are not affected.

The Libreswan Project was notified of an issue causing libreswan to restart under some IKEv2 retransmit scenarios when a connection is configured to use PreSharedKeys (authby=secret) and the connection cannot find a matching configured secret. When such a connection is automatically added on startup using the auto= keyword, it can cause repeated crashes leading to a Denial of Service.

An issue was discovered in Libreswan 3.x and 4.x before 4.12. When an IKEv1 ISAKMP SA Informational Exchange packet contains a Delete/Notify payload followed by further Notifies that act on the ISAKMP SA, such as a duplicated Delete/Notify message, a NULL pointer dereference on the deleted state causes the pluto daemon to crash and restart.

An issue was discovered in Libreswan before 4.12. When an IKEv1 Quick Mode connection configured with ID_IPV4_ADDR or ID_IPV6_ADDR receives an IDcr payload with ID_FQDN, a NULL pointer dereference causes a crash and restart of the pluto daemon. NOTE: the earliest affected version is 4.6.

An issue was discovered in Libreswan before 4.12. When an IKEv2 Child SA REKEY packet contains an invalid IPsec protocol ID number of 0 or 1, an error notify INVALID_SPI is sent back. The notify payload's protocol ID is copied from the incoming packet, but the code that verifies outgoing packets fails an assertion that the protocol ID must be ESP (2) or AH(3) and causes the pluto daemon to crash and restart. NOTE: the earliest affected version is 3.20.

pluto in Libreswan before 4.11 allows a denial of service (responder SPI mishandling and daemon crash) via unauthenticated IKEv1 Aggressive Mode packets. The earliest affected version is 3.28.

A vulnerability was found in the libreswan library. This security issue occurs when an IKEv1 Aggressive Mode packet is received with only unacceptable crypto algorithms, and the response packet is not sent with a zero responder SPI. When a subsequent packet is received where the sender reuses the libreswan responder SPI as its own initiator SPI, the pluto daemon state machine crashes. No remote code execution is possible. This CVE exists because of a CVE-2023-30570 security regression for libreswan package in Red Hat Enterprise Linux 8.8 and Red Hat Enterprise Linux 9.2.

Libreswan 4.9 allows remote attackers to cause a denial of service (assert failure and daemon restart) via crafted TS payload with an incorrect selector length.

Libreswan 4.2 through 4.5 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via a crafted IKEv1 packet because pluto/ikev1.c wrongly expects that a state object exists. This is fixed in 4.6.

An out-of-bounds buffer read flaw was found in the pluto daemon of libreswan from versions 3.27 till 3.31 where, an unauthenticated attacker could use this flaw to crash libreswan by sending specially-crafted IKEv1 Informational Exchange packets. The daemon respawns after the crash.