Detections
Analytics

Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : GnuTLS vulnerabilities (USN-8539-1)

high Nessus Plugin ID 327062

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 host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8539-1 advisory.

 Haruto Kimura discovered that GnuTLS did not properly apply permitted name constraints in certain certificate validation paths. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. (CVE-2026-42011)

 Oleh Konko discovered that GnuTLS incorrectly fell back to Common Name checks for certain URI and SRV subject alternative names. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. (CVE-2026-42012)

 Haruto Kimura and Joshua Rogers discovered that GnuTLS incorrectly fell back to Common Name checks when subject alternative names were oversized. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. (CVE-2026-42013)

 Luigino Camastra and Joshua Rogers discovered that GnuTLS had a use-after-free issue when changing PKCS#11 token security officer PINs in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-42014)

 Zou Dikai discovered that GnuTLS did not properly validate PKCS#12 bag sizes in certain cases. An attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-42015)

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-8539-1

Plugin Details

Severity: High

ID: 327062

File Name: ubuntu_USN-8539-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 7/15/2026

Updated: 7/15/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.6

CVSS v2

Risk Factor: High

Base Score: 8.5

Temporal Score: 6.3

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

CVSS Score Source: CVE-2026-42013

CVSS v3

Risk Factor: High

Base Score: 8.2

Temporal Score: 7.1

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libgnutls-openssl27, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libgnutlsxx28, p-cpe:/a:canonical:ubuntu_linux:libgnutls28-dev, p-cpe:/a:canonical:ubuntu_linux:libgnutls30, p-cpe:/a:canonical:ubuntu_linux:libgnutls-dane0, p-cpe:/a:canonical:ubuntu_linux:guile-gnutls, p-cpe:/a:canonical:ubuntu_linux:libgnutls-dev, p-cpe:/a:canonical:ubuntu_linux:gnutls-bin

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/14/2026

Vulnerability Publication Date: 4/30/2026

Reference Information

CVE: CVE-2026-42011, CVE-2026-42012, CVE-2026-42013, CVE-2026-42014, CVE-2026-42015

USN: 8539-1