Amazon Linux 2 : libvirt, --advisory ALAS2-2026-3873 (ALAS-2026-3873)

high Nessus Plugin ID 341892

Synopsis

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

Description

The version of libvirt installed on the remote host is prior to 4.5.0-36. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3873 advisory.

libvirt: newline injection in network xml dns txt/srv fields allows dnsmasq config directive injection (CVE-2026-61477)

libvirt: Check for empty string condition and skip inclusion of the XML document context in the error message. (CVE-2026-61478)

A flaw was found in libvirt. A local attacker, specifically a process running as the confined `swtpm` user, could exploit a symlink-following vulnerability in the `virFileChownFiles()` function. By planting a symbolic link within the `swtpm` state directory, the attacker could trick the root-level libvirt daemon into changing the ownership of an arbitrary file to the `swtpm` user. This allows for privilege escalation from the `swtpm` sandbox to root-level file ownership control. (CVE-2026-63622)

A flaw was found in libvirt. During storage volume clone or convert operations, newly created volume images were temporarily world-readable. This was caused by the `qemu-img` utility running with overly permissive file creation settings, allowing any local user to read the full guest disk contents. This vulnerability could lead to sensitive information disclosure from guest virtual machines. (CVE-2026-63623)

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

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

Solution

Run 'yum update libvirt' or or 'yum update --advisory ALAS2-2026-3873' to update your system.

Plugin Details

Severity: High

ID: 341892

File Name: al2_ALAS-2026-3873.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 8/31/2026

Updated: 8/31/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.48

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2026-63622

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:libvirt-admin, p-cpe:/a:amazon:linux:libvirt-bash-completion, p-cpe:/a:amazon:linux:libvirt-client, p-cpe:/a:amazon:linux:libvirt-daemon-config-network, p-cpe:/a:amazon:linux:libvirt-daemon-config-nwfilter, p-cpe:/a:amazon:linux:libvirt-daemon-driver-interface, p-cpe:/a:amazon:linux:libvirt-daemon-driver-lxc, p-cpe:/a:amazon:linux:libvirt-daemon-driver-network, p-cpe:/a:amazon:linux:libvirt-daemon-driver-nodedev, p-cpe:/a:amazon:linux:libvirt-daemon-driver-nwfilter, p-cpe:/a:amazon:linux:libvirt-daemon-driver-qemu, p-cpe:/a:amazon:linux:libvirt-daemon-driver-secret, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-core, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-disk, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-gluster, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-iscsi, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-logical, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-mpath, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-rbd, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage-scsi, p-cpe:/a:amazon:linux:libvirt-daemon-driver-storage, p-cpe:/a:amazon:linux:libvirt-daemon-kvm, p-cpe:/a:amazon:linux:libvirt-daemon-lxc, p-cpe:/a:amazon:linux:libvirt-daemon, p-cpe:/a:amazon:linux:libvirt-debuginfo, p-cpe:/a:amazon:linux:libvirt-devel, p-cpe:/a:amazon:linux:libvirt-docs, p-cpe:/a:amazon:linux:libvirt-libs, p-cpe:/a:amazon:linux:libvirt-lock-sanlock, p-cpe:/a:amazon:linux:libvirt-login-shell, p-cpe:/a:amazon:linux:libvirt-nss, p-cpe:/a:amazon:linux:libvirt

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

Exploit Ease: No known exploits are available

Patch Publication Date: 8/31/2026

Vulnerability Publication Date: 8/7/2026

Reference Information

CVE: CVE-2026-61477, CVE-2026-61478, CVE-2026-63622, CVE-2026-63623

Detections

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