CVE-2026-94453 IKEv2 Use-After-Free bug when using IKE-over-TCP
A use-after-free in Libreswan's pluto daemon allows remote attackers to cause denial of service or potentially execute code via IKE-over-TCP.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-94453?
CVE-2026-94453 is a high-severity use after free vulnerability in The Libreswan Project libreswan, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-416
Which versions are affected by CVE-2026-94453?
How do I fix CVE-2026-94453?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-94453 being exploited?
There is no known exploitation of CVE-2026-94453 in the wild and no public exploit code.
Sources
Also known as AZL-108027, DEBIAN-CVE-2026-94453, GHSA-59fc-px6w-3g8v, UBUNTU-CVE-2026-94453.