All vulnerabilities
CVE-2026-94453

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

The Libreswan Project libreswan
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.45%Chance of exploitation activity in the next 30 days, higher than 38% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published13 Oct 2026Updated 16 Oct 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

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.

Text from CVE List

Affected versions 4

  • libreswanaffected: 4.0 through 5.3.2CVE List
  • libreswanaffected: 5.4 through 5.4CVE List
  • libreswanunaffected: 5.3.3CVE List
  • libreswanunaffected: 5.4.1CVE List

References 2