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RHEL 8 : unbound (RHSA-2026:70754)

critical Nessus Plugin ID 349458

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Synopsis

The remote Red Hat host is missing one or more security updates for unbound.

Description

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:70754 advisory.

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

 Security Fix(es):

 * unbound: Unbound: Remote Code Execution Vulnerability in CNAME Synthesis (CVE-2026-82717)

 * unbound: Unbound: Heap buffer overflow via malicious DNSSEC response (CVE-2026-81634)

 * 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 these issues 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-2026:70754.

See Also

https://access.redhat.com/errata/RHSA-2026:70754

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

https://bugzilla.redhat.com/show_bug.cgi?id=2535051

https://bugzilla.redhat.com/show_bug.cgi?id=2535054

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

http://www.nessus.org/u?660ced0a

Plugin Details

Severity: Critical

ID: 349458

File Name: redhat-RHSA-2026-70754.nasl

Version: 1.2

Type: Local

Agent: unix

Published: 9/23/2026

Updated: 9/24/2026

Supported Sensors: Continuous Assessment, Nessus Agent, 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-2026-82717

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

CVSS Score Source: CVE-2026-81642

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:rhel_eus:8.10, p-cpe:/a:redhat:enterprise_linux:python3-unbound, p-cpe:/a:redhat:enterprise_linux:unbound-devel, 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: 9/23/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2026-81634, CVE-2026-81642, CVE-2026-82717

CWE: 122, 787

RHSA: 2026:70754