Debian dsa-6497 : xnest - security update

critical Nessus Plugin ID 345001

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 13 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-6497 advisory.

- ------------------------------------------------------------------------- Debian Security Advisory DSA-6497-1 [email protected] https://www.debian.org/security/ Salvatore Bonaccorso September 12, 2026 https://www.debian.org/security/faq
- -------------------------------------------------------------------------

Package : xorg-server CVE ID : CVE-2026-55999 CVE-2026-56000 Debian Bug : 1141703

Several vulnerabilities were discovered in the Xorg X server, which may result in privilege escalation if the X server is running privileged.

For the stable distribution (trixie), these problems have been fixed in version 2:21.1.16-1.3+deb13u4.

We recommend that you upgrade your xorg-server packages.

For the detailed security status of xorg-server please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/xorg-server

Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: https://www.debian.org/security/

Mailing list: [email protected]

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the xnest packages.

Plugin Details

Severity: Critical

ID: 345001

File Name: debian_DSA-6497.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 9/12/2026

Updated: 9/12/2026

Supported Sensors: 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: 4.9

Percentile: 58.1

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-2026-56000

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

CVSS v4

Risk Factor: Critical

Base Score: 9

Threat Score: 6.1

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:13.0, p-cpe:/a:debian:debian_linux:xnest, p-cpe:/a:debian:debian_linux:xorg-server-source, p-cpe:/a:debian:debian_linux:xserver-common, p-cpe:/a:debian:debian_linux:xserver-xephyr, p-cpe:/a:debian:debian_linux:xserver-xorg-core-udeb, p-cpe:/a:debian:debian_linux:xserver-xorg-core, p-cpe:/a:debian:debian_linux:xserver-xorg-dev, p-cpe:/a:debian:debian_linux:xserver-xorg-legacy, p-cpe:/a:debian:debian_linux:xvfb

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 9/12/2026

Vulnerability Publication Date: 7/8/2026

Reference Information

CVE: CVE-2026-55999, CVE-2026-56000

Detections

Analytics