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Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : .NET vulnerabilities (USN-8420-1)

medium Nessus Plugin ID 320847

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Synopsis

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

Description

The remote Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8420-1 advisory.

 It was discovered that .NET did not properly handle link resolution before file access. A local attacker could use this issue to perform unauthorized file tampering and write arbitrary files outside of the intended extraction directory. (CVE-2026-45491)

 It was discovered that .NET did not properly handle deeply-nested MessagePack arrays. An attacker could use this to cause .NET to consume excessive resources, resulting in a denial of service. (CVE-2026-45591)

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-8420-1

Plugin Details

Severity: Medium

ID: 320847

File Name: ubuntu_USN-8420-1.nasl

Version: 1.3

Type: Local

Agent: unix

Published: 6/12/2026

Updated: 6/22/2026

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

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.76

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

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

CVSS Score Source: CVE-2026-45491

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

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

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

Vulnerability Information

CPE: p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-8.0-source-built-artifacts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:dotnet-host-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-host-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-10.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-targeting-pack-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet9, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-dbg-10.0, cpe:/o:canonical:ubuntu_linux:25.10, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-8.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-host-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-dbg-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-aot-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-targeting-pack-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-dbg-8.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-targeting-pack-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-apphost-pack-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-apphost-pack-9.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-8.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-targeting-pack-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet10, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-aot-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-apphost-pack-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet8, p-cpe:/a:canonical:ubuntu_linux:netstandard-targeting-pack-2.1-8.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-dbg-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-dbg-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-9.0-source-built-artifacts, p-cpe:/a:canonical:ubuntu_linux:netstandard-targeting-pack-2.1-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-hostfxr-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-targeting-pack-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-templates-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-dbg-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-10.0-source-built-artifacts, p-cpe:/a:canonical:ubuntu_linux:dotnet-templates-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-9.0, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:dotnet-hostfxr-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-runtime-9.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-targeting-pack-10.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-sdk-dbg-9.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-dbg-10.0, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:dotnet-templates-10.0, p-cpe:/a:canonical:ubuntu_linux:aspnetcore-runtime-dbg-8.0, p-cpe:/a:canonical:ubuntu_linux:dotnet-hostfxr-9.0

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

Exploit Ease: No known exploits are available

Patch Publication Date: 6/11/2026

Vulnerability Publication Date: 6/9/2026

Reference Information

CVE: CVE-2026-45491, CVE-2026-45591

IAVA: 2026-A-0565, 2026-A-0566

USN: 8420-1