Linux Distros Unpatched Vulnerability : CVE-2026-18477

medium Nessus Plugin ID 331741

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 TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflowsincluding extracting into a newly created directory without using the -P option do not mitigate the issue. (CVE-2026-18477)

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

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 331741

File Name: unpatched_CVE_2026_18477.nasl

Version: 1.3

Type: Local

Agent: unix

Family: Misc.

Published: 8/3/2026

Updated: 8/4/2026

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: Low

Score: 3

Percentile: 23.74

CVSS v2

Risk Factor: Low

Base Score: 3.8

Temporal Score: 3.2

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

CVSS Score Source: CVE-2026-18477

CVSS v3

Risk Factor: Medium

Base Score: 4.4

Temporal Score: 4.1

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

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

Vulnerability Information

CPE: 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:10, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:tar, p-cpe:/a:debian:debian_linux:tar, p-cpe:/a:redhat:enterprise_linux:tar

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: 8/3/2026

Reference Information

CVE: CVE-2026-18477

Detections

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