CVE-2026-39458 BIG-IP DNS Cache vulnerability

High 8.7 Published 13 May 2026 Updated 24 Aug 2026

Attackers can cause a denial of service by sending undisclosed traffic to BIG-IP devices with DNS caching enabled.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-39458?

CVE-2026-39458 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-824

Which versions are affected by CVE-2026-39458?

It affects 21 products.

Products include F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Advanced Web Application Firewall, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager and 15 more.

How do I fix CVE-2026-39458?

No fix has been published for CVE-2026-39458 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-39458 being exploited?

There is no known exploitation of CVE-2026-39458 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-9w3c-r5r8-2fg7.