CVE-2026-42781 BIG-IP FastL4 virtual server vulnerability

High 7.1 Published 13 May 2026 Updated 13 May 2026

Attackers can cause resource exhaustion and denial of service on BIG-IP devices when ePVA acceleration is enabled.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-42781?

CVE-2026-42781 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 13 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

When embedded Packet Velocity Acceleration (ePVA) acceleration is configured, undisclosed local ethernet traffic can cause an increase in ePVA and Traffic Management Microkernel (TMM) resource utilization. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Weakness: CWE-835

Which versions are affected by CVE-2026-42781?

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-2026-42781?

No fix has been published for CVE-2026-42781 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-2026-42781 being exploited?

There is no known exploitation of CVE-2026-42781 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-543h-qfcx-5xww.