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Ubuntu 16.04 LTS : libuser vulnerabilities (USN-8987-1)

high Nessus Plugin ID 375876

Synopsis

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

Description

The remote Ubuntu 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8987-1 advisory.

 It was discovered that libuser did not properly validate the GECOS field when changing user information. A local attacker could possibly use this issue to corrupt the passwd file, resulting in a denial of service.
 (CVE-2015-3245)

 It was discovered that libuser modified the passwd file in place when updating user information. A local attacker could possibly use this issue to cause an inconsistent file state, resulting in a denial of service, or possibly escalate privileges. (CVE-2015-3246)

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 libuser, libuser1 and / or python-libuser packages.

See Also

https://ubuntu.com/security/notices/USN-8987-1

Plugin Details

Severity: High

ID: 375876

File Name: ubuntu_USN-8987-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 11/4/2026

Updated: 11/4/2026

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: Critical

Score: 9.4

Percentile: 99.83

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.3

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

CVSS Score Source: CVE-2015-3246

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 7.1

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libuser1, p-cpe:/a:canonical:ubuntu_linux:libuser, p-cpe:/a:canonical:ubuntu_linux:python-libuser

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: 11/3/2026

Vulnerability Publication Date: 7/23/2015

CISA Known Exploited Vulnerability Due Dates: 9/9/2026

Reference Information

CVE: CVE-2015-3245, CVE-2015-3246

USN: 8987-1