CyberBrief
Subscribe
7.5High

F5 Big-Ip Access Policy Manager

CVE-2026-39458

When a BIG-IP is configured with DNS caching (Such as a DNS profile with caching enabled, SSL Orchestrator, Advanced WAF DoS protection), undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

What this means for your business

  • It affects F5 Big-Ip Access Policy Manager. It matters if your company, or a supplier that handles your data, runs it.
  • An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
  • FIRST's prediction model gives it a 0.3% chance of attack attempts being seen in the next 30 days, ranking above 18% of all known flaws.

What to do

  1. 1Check whether your company or your suppliers run F5 Big-Ip Access Policy Manager, and which version. The affected versions are listed further down this page.
  2. 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

Check if you’re exposedBook a call

Scoring

CVSS
7.5 (v3.1)
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4
8.7
Weakness
CWE-824
Assigned by
f5sirt@f5.com

Dates

Published
2026-05-13
Last modified
2026-08-24
Sources
NVD

Affected products

  • F5 Big-Ip Access Policy Manager17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Advanced Firewall Manager17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Advanced Web Application Firewall17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Analytics17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Application Acceleration Manager17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Application Security Manager17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Application Visibility And Reporting17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Automation Toolchain17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Carrier-Grade Nat17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Container Ingress Services17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Ddos Hybrid Defender17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0
  • F5 Big-Ip Domain Name System17.1.0 - 17.1.3, 17.5.0 - 17.5.1, 16.1.0 - 16.1.6, 21.0.0

As listed in the NVD configuration data. Not a statement about your estate.

References