Libreswan's pluto daemon has a use-after-free vulnerability when a client connecting using IKE over TCP closes the connection and another packet (retransmit or malicious) is received for the same tuple. IKE state is retained in memory after the client closes the connection, storing a pointer to iface_endpoint inside ike_sa.sa->st_iface_endpoint. Once this invalid pointer is used, the daemon crashes and restarts. This vulnerability can be triggered before the remote peer has authenticated itself. Continued exploitation can lead to a denial of service. Remote code execution could be possible. The IKE over TCP option is not enabled by default; only configurations that contain listen-tcp=yes are affected.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to libreswan 5.3.3 or 5.4.1 or later. Patches are available at https://libreswan.org/security/CVE-2026-94453/


Workaround

To temporarily disable IKE over TCP, set listen-tcp=no.

History

Tue, 13 Oct 2026 21:45:00 +0000

Type Values Removed Values Added
Description Libreswan's pluto daemon has a use-after-free vulnerability when a client connecting using IKE over TCP closes the connection and another packet (retransmit or malicious) is received for the same tuple. IKE state is retained in memory after the client closes the connection, storing a pointer to iface_endpoint inside ike_sa.sa->st_iface_endpoint. Once this invalid pointer is used, the daemon crashes and restarts. This vulnerability can be triggered before the remote peer has authenticated itself. Continued exploitation can lead to a denial of service. Remote code execution could be possible. The IKE over TCP option is not enabled by default; only configurations that contain listen-tcp=yes are affected.
Title IKEv2 Use-After-Free bug when using IKE-over-TCP
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: libreswan

Published:

Updated: 2026-10-13T21:27:43.376Z

Reserved: 2026-09-21T17:09:02.116Z

Link: CVE-2026-94453

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-13T22:19:30.253

Modified: 2026-10-13T22:19:30.253

Link: CVE-2026-94453

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses