Detections
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Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : YAML-LibYAML vulnerabilities (USN-8925-1)

critical Nessus Plugin ID 366021

Synopsis

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

Description

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8925-1 advisory.

 Dominique Dumont discovered that YAML-LibYAML did not correctly handle certain reflection operations. If a user or system were tricked into opening a specially crafted file, an attacker could possibly use this issue to delete files. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2017-20285)

 It was discovered that YAML-LibYAML did not correctly handle parsing certain documents. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS.
 (CVE-2019-25777)

 It was discovered that YAML-LibYAML contained a regular expression susceptible to catastrophic backtracking. If a user or automated system were tricked into opening a specially crafted file, an attacker could possibly use this issue to cause a denial of service. (CVE-2026-63676)

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 libyaml-perl package.

See Also

https://ubuntu.com/security/notices/USN-8925-1

Plugin Details

Severity: Critical

ID: 366021

File Name: ubuntu_USN-8925-1.nasl

Version: 1.2

Type: Local

Agent: unix

Published: 10/15/2026

Updated: 10/15/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.45

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

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

CVSS Score Source: CVE-2017-20285

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libyaml-perl

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

Exploit Ease: No known exploits are available

Patch Publication Date: 10/14/2026

Vulnerability Publication Date: 9/14/2026

Reference Information

CVE: CVE-2017-20285, CVE-2019-25777, CVE-2026-63676

USN: 8925-1