CVE-2026-94453

IKEv2 Use-After-Free bug when using IKE-over-TCP

Published Oct 13, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

Vendor Solution

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


Vendor Workaround

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

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Libreswan
Libreswan libreswan
Vendors & Products Libreswan
Libreswan libreswan
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
libreswan
Published
Updated
Oct 16, 2026, 3:31 PM
Reserved
Sep 21, 2026, 5:09 PM
Status
Awaiting Analysis
Published
Oct 13, 2026, 10:19 PM
Modified
Oct 16, 2026, 7:55 PM
Severity
Important
Public date
Oct 5, 2026, 12:00 AM