Amazon Linux 2 : amazon-ssm-agent (ALAS-2026-3933)

high Nessus Plugin ID 351032

Synopsis

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

Description

The version of amazon-ssm-agent installed on the remote host is prior to 3.3.5226.0-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3933 advisory.

Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello. (CVE-2026-42505)

go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5, worktree operations (including checkout, status, and add) resolve symbolic links inside the working tree without confining resolution to the worktree boundary, so a maliciously crafted repository containing a symlink can cause go-git to read from or write to files outside the intended working directory when the repository is cloned and its worktree operations are used. Versions 5.19.2 and 6.0.0-alpha.5.
(CVE-2026-71556)

go-git is an extensible git implementation library written in pure Go. Prior to 5.19.2 and 6.0.0-alpha.5, reference names are not sanitized before being used to construct on-disk paths under the reference storage directory, so a maliciously crafted reference name (for example containing directory-traversal sequences) can cause go-git to write files outside the intended reference storage directory. Versions 5.19.2 and 6.0.0-alpha.5 fix the issue. (CVE-2026-71557)

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 amazon-ssm-agent' or or 'yum update --advisory ALAS2-2026-3933' to update your system.

Plugin Details

Severity: High

ID: 351032

File Name: al2_ALAS-2026-3933.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 9/29/2026

Updated: 9/29/2026

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: Medium

Score: 5.5

Percentile: 95.89

CVSS v2

Risk Factor: High

Base Score: 8.5

Temporal Score: 6.7

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

CVSS Score Source: CVE-2026-71556

CVSS v3

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.4

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

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

Vulnerability Information

CPE: cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:amazon-ssm-agent

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 9/28/2026

Vulnerability Publication Date: 7/7/2026

Reference Information

CVE: CVE-2026-42505, CVE-2026-71556, CVE-2026-71557

IAVB: 2026-B-0193-S

Detections

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