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Amazon Linux 2 : xorg-x11-server, --advisory ALAS2-2026-3268 (ALAS-2026-3268)

high Nessus Plugin ID 311212

Synopsis

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

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3268 advisory.

 XKB Integer Underflow in XkbSetCompatMap() (CVE-2026-33999)

 XSYNC Use-after-free in miSyncTriggerFence() (CVE-2026-34001)

 XKB Out-of-bounds read in CheckModifierMap() (CVE-2026-34002)

 XKB Buffer overflow in CheckKeyTypes() (CVE-2026-34003)

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 xorg-x11-server' or or 'yum update --advisory ALAS2-2026-3268' to update your system.

See Also

https://alas.aws.amazon.com//AL2/ALAS2-2026-3268.html

https://alas.aws.amazon.com/faqs.html

https://explore.alas.aws.amazon.com/CVE-2026-33999.html

https://explore.alas.aws.amazon.com/CVE-2026-34001.html

https://explore.alas.aws.amazon.com/CVE-2026-34002.html

https://explore.alas.aws.amazon.com/CVE-2026-34003.html

Plugin Details

Severity: High

ID: 311212

File Name: al2_ALAS-2026-3268.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 4/30/2026

Updated: 4/30/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

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-2026-34003

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: p-cpe:/a:amazon:linux:xorg-x11-server-common, p-cpe:/a:amazon:linux:xorg-x11-server-xdmx, p-cpe:/a:amazon:linux:xorg-x11-server-xorg, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:xorg-x11-server-xnest, p-cpe:/a:amazon:linux:xorg-x11-server-xvfb, p-cpe:/a:amazon:linux:xorg-x11-server-xephyr, p-cpe:/a:amazon:linux:xorg-x11-server-devel, p-cpe:/a:amazon:linux:xorg-x11-server-xwayland, p-cpe:/a:amazon:linux:xorg-x11-server-source, p-cpe:/a:amazon:linux:xorg-x11-server-debuginfo

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

Exploit Ease: No known exploits are available

Patch Publication Date: 4/30/2026

Vulnerability Publication Date: 4/14/2026

Reference Information

CVE: CVE-2026-33999, CVE-2026-34001, CVE-2026-34002, CVE-2026-34003