CVE-2021-23009 Denial of service in BIG-IP

High 7.5 Published 10 May 2021 Updated 3 Aug 2024

Malformed HTTP/2 requests cause an infinite loop in TMM, leading to a Denial of Service for data plane traffic on BIG-IP devices.

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-2021-23009?

CVE-2021-23009 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 10 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

On BIG-IP version 16.0.x before 16.0.1.1 and 15.1.x before 15.1.3, malformed HTTP/2 requests may cause an infinite loop which causes a Denial of Service for Data Plane traffic. TMM takes the configured HA action when the TMM process is aborted. There is no control plane exposure, this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Weakness: CWE-835

Which versions are affected by CVE-2021-23009?

It affects 14 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 8 more.

How do I fix CVE-2021-23009?

No fix has been published for CVE-2021-23009 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-2021-23009 being exploited?

There is no known exploitation of CVE-2021-23009 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-2qgr-4j3q-qhg6.