Ubuntu 20.04 LTS / 22.04 LTS : Linux kernel vulnerabilities (USN-8388-1)

high Nessus Plugin ID 318842

Synopsis

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

Description

The remote Ubuntu 20.04 LTS / 22.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8388-1 advisory.

It was discovered that the Linux kernel did not properly handle shared page fragments during socket buffer operations, collectively known as Dirty Frag. A logic flaw existed in the XFRM ESP-in-TCP subsystem and in the RxRPC networking subsystem when processing paged fragments. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43284, CVE-2026-43500)

It was discovered that a logic flaw existed in the XFRM ESP-in-TCP subsystem in the Linux kernel when handling socket buffer fragments. This flaw is known as Fragnesia. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43503, CVE-2026-46300)

Qualys discovered that a race condition existed in the ptrace subsystem of the Linux kernel when privileged processes are exiting. An unprivileged local attacker could use this issue to expose sensitive information. (CVE-2026-46333)

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:

- RDS protocol; (CVE-2026-43494)

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-8388-1

Plugin Details

Severity: High

ID: 318842

File Name: ubuntu_USN-8388-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 6/5/2026

Updated: 6/5/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Critical

Score: 10.0

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-2026-46300

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 7.5

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:H/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1109-gcp-fips, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1103-ibm, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-181-generic-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1109-aws-64k, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1061-nvidia-tegra, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1106-oracle, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1109-aws, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1103-raspi, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1109-gcp, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1092-gkeop, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1104-intel-iotg, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-181-generic-lpae, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-181-fips, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1104-nvidia-lowlatency, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1050-nvidia-tegra-igx, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1101-kvm, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1108-realtime, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1105-gke, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1050-nvidia-tegra-igx-rt, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-181-generic, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1104-nvidia, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1109-aws-fips, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1061-nvidia-tegra-rt, p-cpe:/a:canonical:ubuntu_linux:linux-image-5.15.0-1101-intel-iot-realtime

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/4/2026

Vulnerability Publication Date: 5/8/2026

Reference Information

CVE: CVE-2026-43284, CVE-2026-43494, CVE-2026-43500, CVE-2026-43503, CVE-2026-46300, CVE-2026-46333

USN: 8388-1