Amazon Linux 2 : perl-YAML-Syck, --advisory ALAS2-2026-3216 (ALAS-2026-3216)

critical Nessus Plugin ID 304600

Synopsis

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

Description

The version of perl-YAML-Syck installed on the remote host is prior to 1.27-3. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3216 advisory.

YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high- severity heap buffer overflow in the YAML emitter.

The heap overflow occurs when class names exceed the initial 512-byte allocation.

The base64 decoder could read past the buffer end on trailing newlines.

strtok mutated n->type_id in place, corrupting shared node data.

A memory leak occurred in syck_hdlr_add_anchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return. (CVE-2026-4177)

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 perl-YAML-Syck' or or 'yum update --advisory ALAS2-2026-3216' to update your system.

Plugin Details

Severity: Critical

ID: 304600

File Name: al2_ALAS-2026-3216.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 4/1/2026

Updated: 4/1/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

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

CVSS Score Source: CVE-2026-4177

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:perl-yaml-syck, p-cpe:/a:amazon:linux:perl-yaml-syck-debuginfo, cpe:/o:amazon:linux:2

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

Exploit Ease: No known exploits are available

Patch Publication Date: 4/1/2026

Vulnerability Publication Date: 3/16/2026

Reference Information

CVE: CVE-2026-4177

Detections

Analytics