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.
Metrics
Affected Vendors & Products
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.
References
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 |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: libreswan
Published:
Updated: 2026-10-13T21:27:43.376Z
Reserved: 2026-09-21T17:09:02.116Z
Link: CVE-2026-94453
No data.
Status : Received
Published: 2026-10-13T22:19:30.253
Modified: 2026-10-13T22:19:30.253
Link: CVE-2026-94453
No data.
OpenCVE Enrichment
No data.
Weaknesses