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F5 Networks BIG-IP : NLnet Labs Unbound vulnerability (K000162456)

high Nessus Plugin ID 330218

Synopsis

The remote device is missing a vendor-supplied security patch.

Description

The version of F5 Networks BIG-IP installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the K000162456 advisory.

 CVE-2026-41292NLnet Labs Unbound up to and including version 1.25.0 is vulnerable to a degradation of service attack related to parsing long lists of incoming EDNS options. An adversary sending queries with too many EDNS options can hold Unbound threads hostage while they are parsing and creating internal data structures for the options. Coordinated attacks can result in degradation and/or denial of service.
 Unbound 1.25.1 contains a patch with a fix to limit acceptable incoming EDNS options (100).CVE-2026-42944NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query.
 A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.

Tenable has extracted the preceding description block directly from the F5 Networks BIG-IP 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

The vendor has acknowledged the vulnerability, but no solution has been provided.
Refer to the vendor for remediation guidance.

See Also

https://my.f5.com/manage/s/article/K000162456

Plugin Details

Severity: High

ID: 330218

File Name: f5_bigip_SOL000162456.nasl

Version: 1.1

Type: Local

Published: 7/27/2026

Updated: 7/27/2026

Configuration: Enable paranoid mode

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.75

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-42944

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:N/A:H

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

CVSS v4

Risk Factor: High

Base Score: 8.7

Threat Score: 6.6

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

CPE: cpe:/a:f5:big-ip_domain_name_system, cpe:/a:f5:big-ip_global_traffic_manager, cpe:/h:f5:big-ip

Required KB Items: Host/local_checks_enabled, Settings/ParanoidReport, Host/BIG-IP/hotfix, Host/BIG-IP/modules, Host/BIG-IP/version

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 5/20/2026

Reference Information

CVE: CVE-2026-41292, CVE-2026-42944