CVE-2021-22999 Denial of service in BIG-IP

High 7.5 Published 31 Mar 2021 Updated 3 Aug 2024

A slow client closing connections prematurely can cause BIG-IP to retain streams indefinitely, leading to resource exhaustion and denial of service.

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-2021-22999?

CVE-2021-22999 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 31 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

On versions 15.0.x before 15.1.0 and 14.1.x before 14.1.4, the BIG-IP system provides an option to connect HTTP/2 clients to HTTP/1.x servers. When a client is slow to accept responses and it closes a connection prematurely, the BIG-IP system may indefinitely retain some streams unclosed. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

Which versions are affected by CVE-2021-22999?

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-2021-22999?

No fix has been published for CVE-2021-22999 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-2021-22999 being exploited?

There is no known exploitation of CVE-2021-22999 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-rr8c-wqrp-cv55.