CVE-2020-5921 Denial of service in BIG-IP

High 7.5 Published 26 Aug 2020 Updated 4 Aug 2024

A SYN flood attack can exhaust memory on multi-blade VIPRION hosts, causing MCPD failure 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-2020-5921?

CVE-2020-5921 is a high-severity denial of service vulnerability in F5 Big-Ip Access Policy Manager, published on 26 Aug 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

in BIG-IP versions 15.1.0-15.1.0.4, 15.0.0-15.0.1.3, 14.1.0-14.1.2.6, 13.1.0-13.1.3.4, 12.1.0-12.1.5.1, and 11.6.1-11.6.5.2, Syn flood causes large number of MCPD context messages destined to secondary blades consuming memory leading to MCPD failure. This issue affects only VIPRION hosts with two or more blades installed. Single-blade VIPRION hosts are not affected.

Which versions are affected by CVE-2020-5921?

It affects 11 products.

Products include F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager, F5 Big-Ip Domain Name System and 5 more.

How do I fix CVE-2020-5921?

No fix has been published for CVE-2020-5921 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-2020-5921 being exploited?

There is no known exploitation of CVE-2020-5921 in the wild and no public exploit code.

All F5 Big-Ip Access Policy Manager vulnerabilities

Sources

Also known as GHSA-3wm8-xffc-5pg9.