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Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : GnuTLS vulnerabilities (USN-8284-1)

critical Nessus Plugin ID 316043

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-8284-1 advisory.

 Joshua Rogers discovered that GnuTLS did not properly handle malformed DTLS handshake fragments in certain cases. A remote attacker could possibly use this issue to obtain sensitive information, or cause a denial of service. (CVE-2026-33845)

 Haruto Kimura, Oscar Reparaz, and Zou Dikai discovered that GnuTLS did not properly validate DTLS handshake fragment lengths in certain cases. A remote attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-33846)

 Oleh Konko and Joshua Rogers discovered that GnuTLS did not properly validate OCSP responses in certain cases. A remote attacker could possibly use this issue to bypass certificate revocation checks, leading to a machine-in-the-middle attack. (CVE-2026-3832)

 Oleh Konko and Joshua Rogers discovered that GnuTLS did not properly handle case-insensitive name constraints in certain cases. A remote attacker could possibly use this issue to bypass certificate validation, leading to a machine-in-the-middle attack. (CVE-2026-3833)

 Joshua Rogers discovered that GnuTLS did not properly order DTLS packets with duplicate sequence numbers in certain cases. A remote attacker could possibly use this issue to cause GnuTLS to crash, resulting in a denial of service. (CVE-2026-42009)

 Joshua Rogers discovered that GnuTLS did not properly handle usernames containing NUL characters in certain RSA-PSK configurations. A remote attacker could possibly use this issue to bypass authentication and gain unintended access to services. (CVE-2026-42010)

 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)

 Joshua Rogers discovered that GnuTLS did not properly handle very short premaster secrets in certain RSA key exchange cases with PKCS#11-backed server keys. A remote attacker could possibly use this issue to obtain sensitive information. (CVE-2026-5260)

 Doria Tang discovered that GnuTLS did not perform PKCS#7 padding checks in constant time in certain cases.
 A remote attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-5419)

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-8284-1

Plugin Details

Severity: Critical

ID: 316043

File Name: ubuntu_USN-8284-1.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 5/21/2026

Updated: 5/21/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

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-2026-42010

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: p-cpe:/a:canonical:ubuntu_linux:libgnutls30, p-cpe:/a:canonical:ubuntu_linux:gnutls-bin, p-cpe:/a:canonical:ubuntu_linux:guile-gnutls, p-cpe:/a:canonical:ubuntu_linux:libgnutls-dane0, p-cpe:/a:canonical:ubuntu_linux:libgnutls-openssl27, p-cpe:/a:canonical:ubuntu_linux:libgnutls28-dev, p-cpe:/a:canonical:ubuntu_linux:libgnutlsxx28, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libgnutls-dane0t64, p-cpe:/a:canonical:ubuntu_linux:libgnutls-openssl27t64, p-cpe:/a:canonical:ubuntu_linux:libgnutls30t64, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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: 5/20/2026

Vulnerability Publication Date: 4/30/2026

Reference Information

CVE: CVE-2026-33845, CVE-2026-33846, CVE-2026-3832, CVE-2026-3833, CVE-2026-42009, CVE-2026-42010, CVE-2026-42011, CVE-2026-42012, CVE-2026-42013, CVE-2026-42014, CVE-2026-42015, CVE-2026-5260, CVE-2026-5419

USN: 8284-1