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.