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Ubuntu 20.04 LTS / 24.04 LTS / 26.04 LTS : FastNetMon vulnerabilities (USN-8429-1)

critical Nessus Plugin ID 321184

Synopsis

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

Description

The remote Ubuntu 20.04 LTS / 24.04 LTS / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8429-1 advisory.

 It was discovered that FastNetMon incorrectly validated prefix lengths when decoding BGP NLRI data. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48686)

 It was discovered that FastNetMon incorrectly sanitized input in the Juniper router integration plugin. An attacker could possibly use this issue to execute arbitrary commands. (CVE-2026-48687)

 It was discovered that FastNetMon incorrectly handled buffer bounds checks when processing network traffic. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48689)

 It was discovered that FastNetMon incorrectly handled encoding the BGP AS_PATH attribute. A remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-48691)

 It was discovered that FastNetMon incorrectly validated IP address input in the Juniper router integration plugin. An attacker could possibly use this issue to inject arbitrary router configuration commands.
 (CVE-2026-48694)

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 fastnetmon package.

See Also

https://ubuntu.com/security/notices/USN-8429-1

Plugin Details

Severity: Critical

ID: 321184

File Name: ubuntu_USN-8429-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 6/16/2026

Updated: 6/16/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

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

CVSS Score Source: CVE-2026-48691

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:fastnetmon

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: 6/15/2026

Vulnerability Publication Date: 5/26/2026

Reference Information

CVE: CVE-2026-48686, CVE-2026-48687, CVE-2026-48689, CVE-2026-48691, CVE-2026-48694

USN: 8429-1