Linux Distros Unpatched Vulnerability : CVE-2026-56000

critical Nessus Plugin ID 325687

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- Local attackers with a X connection able to provide GLX commit to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a Heap Use After Free, due to CommonMakeCurrent() pointing into potentially reallocated memory. (CVE-2026-56000)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2026-56000

https://security-tracker.debian.org/tracker/CVE-2026-56000

https://ubuntu.com/security/CVE-2026-56000

Plugin Details

Severity: Critical

ID: 325687

File Name: unpatched_CVE_2026_56000.nasl

Version: 1.12

Type: Local

Agent: unix

Family: Misc.

Published: 7/8/2026

Updated: 7/25/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless 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: Low

Base Score: 3.6

Temporal Score: 3.1

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

CVSS Score Source: CVE-2026-56000

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.1

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:U/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:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:centos:centos:8, cpe:/o:debian:debian_linux:11.0, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, cpe:/o:debian:debian_linux:14.0, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:canonical:ubuntu_linux:xorg-server-hwe-16.04, p-cpe:/a:canonical:ubuntu_linux:xorg-server-hwe-18.04, p-cpe:/a:canonical:ubuntu_linux:xorg-server, p-cpe:/a:canonical:ubuntu_linux:xwayland, p-cpe:/a:centos:centos:xorg-x11-server-common, p-cpe:/a:centos:centos:xorg-x11-server-devel, p-cpe:/a:centos:centos:xorg-x11-server-source, p-cpe:/a:centos:centos:xorg-x11-server-xdmx, p-cpe:/a:centos:centos:xorg-x11-server-xephyr, p-cpe:/a:centos:centos:xorg-x11-server-xnest, p-cpe:/a:centos:centos:xorg-x11-server-xorg, p-cpe:/a:centos:centos:xorg-x11-server-xvfb, p-cpe:/a:centos:centos:xorg-x11-server-xwayland, p-cpe:/a:centos:centos:xorg-x11-server, p-cpe:/a:debian:debian_linux:xorg-server, p-cpe:/a:debian:debian_linux:xwayland, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-common, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-devel, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-source, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xdmx, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xephyr, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xnest, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xorg, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xvfb, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server-xwayland, p-cpe:/a:redhat:enterprise_linux:xorg-x11-server

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/8/2026

Reference Information

CVE: CVE-2026-56000