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Ubuntu 22.04 LTS / 24.04 LTS / 25.10 / 26.04 LTS : Unbound vulnerabilities (USN-8282-1)

critical Nessus Plugin ID 316076

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-8282-1 advisory.

 Andrew Griffiths discovered that Unbound did not properly handle certain DNSCrypt packets. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service.
 (CVE-2026-32792)

 Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation in certain situations. A remote attacker could possibly use this issue to execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-33278)

 Qifan Zhang discovered that Unbound incorrectly handled certain ghost domain name records. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-40622)

 Qifan Zhang discovered that Unbound did not properly limit processing of long EDNS option lists. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-41292)

 Qifan Zhang discovered that Unbound incorrectly handled jostle logic under certain circumstances. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-42534)

 Qifan Zhang discovered that Unbound did not properly bound NSEC3 hash calculations. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service.
 (CVE-2026-42923)

 Qifan Zhang discovered that Unbound incorrectly handled multiple EDNS options in certain situations. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS.
 (CVE-2026-42944)

 Qifan Zhang discovered that Unbound incorrectly handled DNSSEC validation of malicious content. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service.
 (CVE-2026-42959)

 TaoFei Guo, Yang Luo, and JianJun Chen discovered that Unbound incorrectly handled delegation processing in certain situations. A remote attacker could possibly use this issue to poison the DNS cache and obtain sensitive information. (CVE-2026-42960)

 Qifan Zhang discovered that Unbound did not properly bound name compression in certain cases. A remote attacker could possibly use this issue to cause Unbound to use excessive resources, leading to a denial of service. (CVE-2026-44390)

 Qifan Zhang discovered that Unbound had a use-after-free issue in RPZ handling. A remote attacker could possibly use this issue to cause Unbound to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.10, and Ubuntu 26.04 LTS. (CVE-2026-44608)

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-8282-1

Plugin Details

Severity: Critical

ID: 316076

File Name: ubuntu_USN-8282-1.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: 7.1

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-33278

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

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

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

CVSS Score Source: CVE-2026-42960

CVSS v4

Risk Factor: Critical

Base Score: 10

Threat Score: 9.1

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:unbound-anchor, p-cpe:/a:canonical:ubuntu_linux:libunbound-dev, p-cpe:/a:canonical:ubuntu_linux:python3-unbound, p-cpe:/a:canonical:ubuntu_linux:unbound, p-cpe:/a:canonical:ubuntu_linux:unbound-host, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libunbound8, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/20/2026

Vulnerability Publication Date: 5/20/2026

Reference Information

CVE: CVE-2026-32792, CVE-2026-33278, CVE-2026-40622, CVE-2026-41292, CVE-2026-42534, CVE-2026-42923, CVE-2026-42944, CVE-2026-42959, CVE-2026-42960, CVE-2026-44390, CVE-2026-44608

USN: 8282-1