CVE-2026-94453
Description
A use-after-free flaw was found in Libreswan's IKE-over-TCP handling. When a TCP connection closes and additional packet processing occurs for the same connection tuple, the IKE daemon may access a previously freed interface endpoint object. A remote, unauthenticated attacker may exploit this flaw to cause the pluto daemon to crash and restart, resulting in denial of service.
Statement
Red Hat Product Security has rated this vulnerability as having an Important security impact. A remote, unauthenticated attacker may exploit a use-after-free in Libreswan's IKE-over-TCP handling before peer authentication to cause the IKE daemon to crash and restart. Repeated exploitation can result in denial of service.
The vulnerability affects only configurations that explicitly enable IKE-over-TCP using listen-tcp=yes; this option is not enabled by default. Consequently, exposure is limited to systems configured to accept IKE-over-TCP connections.
Mitigation
If IKE-over-TCP is not required, administrators can temporarily mitigate this vulnerability by setting `listen-tcp=no` in the Libreswan configuration. This disables the vulnerable IKE-over-TCP functionality.
If IKE-over-TCP is required, administrators should restrict access to the listener to trusted peers where practical and apply the appropriate security update once available.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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