CVE-2024-3652: IKEv1 default AH/ESP responder can cause libreswan to abort and restart

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-11 · updated 2026-06-17
Weakness: CWE-404

Description

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.

Affected products

The Libreswan Project libreswan: from 3.22 before 4.15 — fixed in 4.15

How to fix

Upgrade to a fixed version: The Libreswan Project libreswan 4.15. Check the vendor advisory for mitigations.

References

http://www.openwall.com/lists/oss-security/2024/04/18/2
https://libreswan.org/security/CVE-2024-3652
http://www.openwall.com/lists/oss-security/2024/04/18/2
https://libreswan.org/security/CVE-2024-3652

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