RHEL 9 : unbound (RHSA-2026:55841)

high Nessus Plugin ID 337339

Synopsis

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

Description

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:55841 advisory.

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

Security Fix(es):

* unbound: Unbound: Cache poisoning via insufficient RRSIG.Labels validation and premature cache writes (CVE-2026-44690)

* unbound: Unbound: Denial of Service via malformed EDNS Report-Channel option (CVE-2026-55973)

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-2026:55841.

Plugin Details

Severity: High

ID: 337339

File Name: redhat-RHSA-2026-55841.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Red Hat Local Security Checks

Published: 8/18/2026

Updated: 8/18/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.95

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-44690

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

CPE: cpe:/o:redhat:enterprise_linux:9, cpe:/o:redhat:rhel_eus:9.8, p-cpe:/a:redhat:enterprise_linux:python3-unbound, p-cpe:/a:redhat:enterprise_linux:unbound-devel, p-cpe:/a:redhat:enterprise_linux:unbound-dracut, 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: 8/17/2026

Vulnerability Publication Date: 7/22/2026

Reference Information

CVE: CVE-2026-44690, CVE-2026-55973

CWE: 805

RHSA: 2026:55841

Detections

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