Amazon Linux 2 : libreswan (ALAS-2026-4068)

high Nessus Plugin ID 374349

Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of libreswan installed on the remote host is prior to 3.25-4.8. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-4068 advisory.

In Libreswan before 5.3.2, when the operating system and Libreswan are running in FIPS mode and at least one CA certificate is loaded, a malformed X.509 certificate payload can cause the pluto daemon to abort on an assertion. In FIPS mode, add_decoded_cert() calls CERT_ExtractPublicKey() and asserts the result is non-NULL, but the function returns NULL when public key extraction fails (for example when the RSA exponent is 0), triggering the assertion failure. A remote, unauthenticated attacker can send such a corrupt CERT payload (over IKEv1 or IKEv2) before authentication completes, crashing and restarting the daemon; repeated sending causes a sustained denial of service. Remote code execution is not possible.
Versions 3.0 through 5.3.1 are affected. (CVE-2026-14957)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Run 'yum update libreswan' or or 'yum update --advisory ALAS2-2026-4068' to update your system.

Plugin Details

Severity: High

ID: 374349

File Name: al2_ALAS-2026-4068.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 10/30/2026

Updated: 10/30/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.68

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-14957

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:libreswan-debuginfo, p-cpe:/a:amazon:linux:libreswan

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 10/30/2026

Vulnerability Publication Date: 7/17/2026

Reference Information

CVE: CVE-2026-14957

IAVA: 2026-A-0792-S

Detections

Analytics