Amazon Linux 2023 : amazon-ssm-agent (ALAS2023-2026-3428)

high Nessus Plugin ID 379816

Synopsis

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

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3428 advisory.

When coalescing adjacent text nodes in addText and fosterParent, appending to an existing TextNode's Data via string concatenation (n.Data += text) reallocated and copied the accumulated string on every token.
Inputs containing many short text runs separated by ignored end tags (such as a</x>) caused O(n^2) allocations and byte copies. Accumulate coalesced text in per-node byte slices during parsing and materialize Data strings once at the end of parse. (CVE-2026-78661)

In childTextNodesAreLiteral, walking up the tree previously stopped at the nearest foreign ancestor once an HTML integration point was found. However, that integration point may itself be a descendant of an element that was foster-parented into a foreign namespace (such as <mglyph> or <malignmark> fostered under <mtext>), causing a parser to resolve the subtree in a different foreign namespace upon re-parsing the rendered output. Continue walking the full ancestor chain and verify that every transition from a non- empty namespace occurs at an HTML integration point before emitting literal text. (CVE-2026-97045)

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 amazon-ssm-agent --releasever 2023.12.20261112' or or 'dnf update --advisory ALAS2023-2026-3428 --releasever 2023.12.20261112' to update your system.

Plugin Details

Severity: High

ID: 379816

File Name: al2023_ALAS2023-2026-3428.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 11/12/2026

Updated: 11/12/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.88

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-78661

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:H/I:N/A:N

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

Vulnerability Information

CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:amazon-ssm-agent

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

Exploit Ease: No known exploits are available

Patch Publication Date: 11/12/2026

Vulnerability Publication Date: 10/27/2026

Reference Information

CVE: CVE-2026-78661, CVE-2026-97045

Detections

Analytics