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F5 Networks BIG-IP : NLnet Labs Unbound vulnerability (K000162865)
high Nessus Plugin ID 334952
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 a vulnerability as referenced in the K000162865 advisory.NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a locking inconsistency vulnerability that when certain conditions are met (multi-threaded, RPZ XFR reload, RPZ zone with 'rpz-nsip'/'rpz- nsdname' triggers) it could result in heap use-after-free and eventual crash. An adversary can exploit the vulnerability if conditions are first met on a vulnerable Unbound, i.e., multi-threaded, an RPZ zone with 'rpz-nsip'/'rpz-nsdname' triggers and an ongoing XFR for that RPZ zone. Local RPZ files do not trigger the vulnerability. If the timing is right and an XFR happens at the same time another thread needs to read that RPZ zone, the reader may not hold the lock long enough and the thread applying the XFR may free objects that the reader is about to walk causing the use-after-free. Unbound 1.25.1 contains a patch with a fix to the locking code.(CVE-2026-44608)
Tenable has extracted the preceding description block directly from the F5 Networks BIG-IP 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
The vendor has acknowledged the vulnerability, but no solution has been provided.Refer to the vendor for remediation guidance.
See Also
Plugin Details
Severity: High
ID: 334952
File Name: f5_bigip_SOL000162865.nasl
Version: 1.1
Type: Local
Published: 8/12/2026
Updated: 8/12/2026
Configuration: Enable paranoid mode
Supported Sensors: Nessus
Risk Information
VPR
Risk Factor: Low
Score: 3
Percentile: 23.76
CVSS v2
Risk Factor: Medium
Base Score: 5.4
Temporal Score: 4
Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:C
CVSS Score Source: CVE-2026-44608
CVSS v3
Risk Factor: Medium
Base Score: 5.9
Temporal Score: 5.2
Vector: CVSS:3.0/AV:N/AC:H/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: 8.2
Threat Score: 4.6
Threat Vector: CVSS:4.0/E:U
Vector: CVSS:4.0/AV:N/AC:H/AT:P/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-2026-44608