Linux Distros Unpatched Vulnerability : CVE-2026-56003

high Nessus Plugin ID 325683

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.

- A heap buffer overflow due to missing size checking in the property buffer when parsing PCF files in libXfont2 ComputeScaledProperties() before libXfont2 before 2.0.8 could be used by attackers using authenticated X clients to execute code within the X server. (CVE-2026-56003)

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-2026-56003

https://ubuntu.com/security/CVE-2026-56003

Plugin Details

Severity: High

ID: 325683

File Name: unpatched_CVE_2026_56003.nasl

Version: 1.11

Type: Local

Agent: unix

Family: Misc.

Published: 7/8/2026

Updated: 7/29/2026

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

Base Score: 7.5

Temporal Score: 6.4

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

CVSS Score Source: CVE-2026-56003

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.1

Vector: CVSS:3.0/AV:N/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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:canonical:ubuntu_linux:libxfont2, p-cpe:/a:canonical:ubuntu_linux:libxfont, p-cpe:/a:centos:centos:libxfont2-devel, p-cpe:/a:centos:centos:libxfont2, p-cpe:/a:redhat:enterprise_linux:libxfont2-devel, p-cpe:/a:redhat:enterprise_linux:libxfont2

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/8/2026

Reference Information

CVE: CVE-2026-56003