Amazon Linux 2023 : acl, libacl, libacl-devel (ALAS2023-2026-1986)

high Nessus Plugin ID 328504

Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1986 advisory.

A flaw was found in the `acl` component, specifically within its `libacl` pathname-based functions. A local attacker could exploit this vulnerability by using a symbolic link to replace a pathname component.
This could allow the attacker to redirect access control list (ACL) read or write operations to arbitrary files or directories, leading to unauthorized manipulation of ACLs and ultimately local privilege escalation. (CVE-2026-54369)

A time-of-check to time-of-use (TOCTOU) race condition vulnerability was found in acl. By replacing a pathname component with a symbolic link between a security check and subsequent file operations, an attacker can redirect file access control list operations. This occurs when privileged processes invoke `getfacl` or `setfacl` over an attacker-controlled path, potentially leading to local privilege escalation. (CVE-2026-54370)

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 'dnf update acl --releasever 2023.12.20260720' or or 'dnf update --advisory ALAS2023-2026-1986 --releasever 2023.12.20260720' to update your system.

Plugin Details

Severity: High

ID: 328504

File Name: al2023_ALAS2023-2026-1986.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 7/20/2026

Updated: 7/20/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.64

CVSS v2

Risk Factor: Medium

Base Score: 6.2

Temporal Score: 4.6

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

CVSS Score Source: CVE-2026-54369

CVSS v3

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.2

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

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

CVSS v4

Risk Factor: High

Base Score: 8.4

Threat Score: 5.8

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:acl-debuginfo, p-cpe:/a:amazon:linux:acl-debugsource, p-cpe:/a:amazon:linux:acl, p-cpe:/a:amazon:linux:libacl-debuginfo, p-cpe:/a:amazon:linux:libacl-devel, p-cpe:/a:amazon:linux:libacl

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/20/2026

Vulnerability Publication Date: 6/29/2026

Reference Information

CVE: CVE-2026-54369, CVE-2026-54370

Detections

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