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Ubuntu 18.04 LTS : Linux kernel vulnerabilities (USN-8281-1)

high Nessus Plugin ID 315735

Synopsis

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

Description

The remote Ubuntu 18.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8281-1 advisory.

 It was discovered that the Linux kernel algif_aead module did not properly handle in-place cryptographic operations. This flaw is known as Copy Fail. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-31431)

 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;

 - Packet sockets; (CVE-2026-31504, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078)

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-8281-1

Plugin Details

Severity: High

ID: 315735

File Name: ubuntu_USN-8281-1.nasl

Version: 1.2

Type: Local

Agent: unix

Published: 5/20/2026

Updated: 5/21/2026

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: 9.5

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.9

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

CVSS Score Source: CVE-2026-43078

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5.3

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

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

CVSS Score Source: CVE-2026-43077

CVSS v4

Risk Factor: High

Base Score: 8.6

Threat Score: 8.6

Threat Vector: CVSS:4.0/E:A

Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2026-31431

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-250-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1192-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1174-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1154-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1147-fips, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-1185-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-250-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-2093-gcp-fips, p-cpe:/a:canonical:ubuntu_linux:linux-image-4.15.0-2130-aws-fips

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: 5/19/2026

Vulnerability Publication Date: 4/9/2024

CISA Known Exploited Vulnerability Due Dates: 5/15/2026

Exploitable With

Core Impact

Metasploit (Copy Fail AF_ALG + authencesn Page-Cache Write)

Reference Information

CVE: CVE-2026-31431, CVE-2026-31504, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078

USN: 8281-1