CVE-2026-42920 BIG-IP DTLS Vulnerability

High 8.7 Published 13 May 2026 Updated 13 May 2026

Attackers can cause a denial of service on F5 BIG-IP devices by sending specific traffic when dynamic record sizing is enabled on UDP virtual servers.

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-2026-42920?

CVE-2026-42920 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 Client SSL profile is configured with Allow Dynamic Record Sizing on a UDP virtual server, 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-835

Which versions are affected by CVE-2026-42920?

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-2026-42920?

No fix has been published for CVE-2026-42920 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-2026-42920 being exploited?

There is no known exploitation of CVE-2026-42920 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-xgx2-84j2-cx9m.