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RHEL 9 : unbound (RHSA-2026:71610)

critical Nessus Plugin ID 349751

Synopsis

The remote Red Hat host is missing a security update for unbound.

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2026:71610 advisory.

 The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

 Security Fix(es):

 * unbound: Unbound: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY (CVE-2026-81642)

 For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the RHEL unbound package based on the guidance in RHSA-2026:71610.

See Also

https://access.redhat.com/errata/RHSA-2026:71610

https://access.redhat.com/security/updates/classification/#critical

https://bugzilla.redhat.com/show_bug.cgi?id=2535059

http://www.nessus.org/u?34485f93

Plugin Details

Severity: Critical

ID: 349751

File Name: redhat-RHSA-2026-71610.nasl

Version: 1.1

Type: Local

Agent: unix

Published: 9/24/2026

Updated: 9/24/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.9

Percentile: 96.54

Vendor

Vendor Severity: Critical

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-2026-81642

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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:U/RL:O/RC:C

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:redhat:rhel_e4s:9.2, p-cpe:/a:redhat:enterprise_linux:python3-unbound, p-cpe:/a:redhat:enterprise_linux:unbound-libs, p-cpe:/a:redhat:enterprise_linux:unbound

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 9/24/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2026-81642

CWE: 122

RHSA: 2026:71610