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Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : Ubuntu Advantage Tools (pro client) vulnerabilities (USN-8555-1)

critical Nessus Plugin ID 327616

Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8555-1 advisory.

 Bilal Teke discovered that Ubuntu Advantage Tools exposed the Pro bearer token in command-line arguments when validating APT credentials. A local attacker could possibly use this issue to obtain sensitive information and gain unauthorized access to Ubuntu Pro repositories. (CVE-2026-9494)

 Frederick Jerusha discovered that Ubuntu Advantage Tools did not properly validate data received from the contract server when writing APT source files. An attacker could possibly use this issue to inject arbitrary APT configuration and execute arbitrary code. (CVE-2026-11386)

 Mateusz Gierblinski discovered that Ubuntu Advantage Tools did not properly handle symbolic links when collecting diagnostic logs. A local attacker could possibly use this issue to obtain sensitive information from files owned by the administrator. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-12391)

Tenable has extracted the preceding description block directly from the Ubuntu 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

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-8555-1

Plugin Details

Severity: Critical

ID: 327616

File Name: ubuntu_USN-8555-1.nasl

Version: 1.2

Type: Local

Agent: unix

Published: 7/17/2026

Updated: 7/18/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 94.06

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

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

CVSS Score Source: CVE-2026-11386

CVSS v3

Risk Factor: Critical

Base Score: 9

Temporal Score: 7.8

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:ubuntu-advantage-pro, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:ubuntu-pro-auto-attach, p-cpe:/a:canonical:ubuntu_linux:ubuntu-pro-client, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:ubuntu-advantage-tools, p-cpe:/a:canonical:ubuntu_linux:ubuntu-pro-client-l10n, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/16/2026

Vulnerability Publication Date: 7/16/2026

Reference Information

CVE: CVE-2026-11386, CVE-2026-12391, CVE-2026-9494

USN: 8555-1