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Ubuntu 18.04 LTS / 20.04 LTS : Linux kernel (Azure) vulnerabilities (USN-7939-1)

high Nessus Plugin ID 279031

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Synopsis

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

Description

The remote Ubuntu 18.04 LTS / 20.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-7939-1 advisory.

 Jean-Claude Graf, Sandro Regge, Ali Hajiabadi, and Kaveh Razavi discovered that the Linux kernel contained insufficient branch predictor isolation between a guest and a userspace hypervisor for certain processors. This flaw is known as VMSCAPE. An attacker in a guest VM could possibly use this to expose sensitive information from the host OS. (CVE-2025-40300)

 Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems:

 - Cryptographic API;

 - ACPI drivers;

 - HSI subsystem;

 - I3C subsystem;

 - InfiniBand drivers;

 - Media drivers;

 - Network drivers;

 - Pin controllers subsystem;

 - AFS file system;

 - F2FS file system;

 - SMB network file system;

 - Padata parallel execution mechanism;

 - Timer subsystem;

 - Tracing infrastructure;

 - Memory management;

 - Appletalk network protocol;

 - Networking core;

 - Netfilter; (CVE-2022-49026, CVE-2022-49390, CVE-2023-52854, CVE-2024-35867, CVE-2024-47691, CVE-2024-49935, CVE-2024-50061, CVE-2024-50067, CVE-2024-50095, CVE-2024-50196, CVE-2024-53090, CVE-2024-53218, CVE-2024-56664, CVE-2025-21727, CVE-2025-21855, CVE-2025-37838, CVE-2025-37958, CVE-2025-38352, CVE-2025-38666, CVE-2025-39964, CVE-2025-39993, CVE-2025-40018)

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 kernel package.

See Also

https://ubuntu.com/security/notices/USN-7939-1

Plugin Details

Severity: High

ID: 279031

File Name: ubuntu_USN-7939-1.nasl

Version: 1.1

Type: local

Agent: unix

Published: 12/17/2025

Updated: 12/17/2025

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

Risk Information

VPR

Risk Factor: Critical

Score: 9.4

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.6

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

CVSS Score Source: CVE-2025-21855

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.2

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:F/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.4.0-1156-azure

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 12/16/2025

Vulnerability Publication Date: 7/21/2021

CISA Known Exploited Vulnerability Due Dates: 9/25/2025

Reference Information

CVE: CVE-2022-49026, CVE-2022-49390, CVE-2023-52854, CVE-2024-35867, CVE-2024-47691, CVE-2024-49935, CVE-2024-50061, CVE-2024-50067, CVE-2024-50095, CVE-2024-50196, CVE-2024-53090, CVE-2024-53218, CVE-2024-56664, CVE-2025-21727, CVE-2025-21855, CVE-2025-37838, CVE-2025-37958, CVE-2025-38352, CVE-2025-38666, CVE-2025-39964, CVE-2025-39993, CVE-2025-40018, CVE-2025-40300

USN: 7939-1