IKEv1 default AH/ESP responder can cause libreswan to abort and restart

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.

Scores

EPSS (exploitation in 30 days)

0.80% · top 43% of all CVEs (7 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.

Weakness

• IKEv1 with default AH/ESP configuration can cause libreswan to abort and restart
• CWE-404 Improper Resource Shutdown or Release (opens in a new tab)All about CWE-404 and its CVEs

Affected products

• The Libreswan Project (www.libreswan.org) · libreswan

  • affected 3.22 – ≤ 4.14
  • unaffected 5.0

What to do

Solution: This issue is fixed in 4.15 and all later versions.

Workaround: As a workaround, adding an esp= line to all IKEv1 connections works around the issue. An example covering most common default configurations would be: esp=aes-sha2_512,aes-sha1,aes-sha2_256,aes-md5,3des-sha1,3des-md5.

References (2)

• CVE-2024-3652 (opens in a new tab)vendor-advisoryx_transferred
• http://www.openwall.com/lists/oss-security/2024/04/18/2 (opens in a new tab)x_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2024-3652](https://trackcve.app/badge/CVE-2024-3652.svg)](https://trackcve.app/cve/CVE-2024-3652)

Record last updated 27 Feb 2026, 15:19 UTC.