CVE-2020-27718: F5 BIG-IP Advanced Web Application Firewall

High severity, CVSS 7.5. EPSS: 1% chance of exploitation in the next 30 days.

When a BIG-IP ASM or Advanced WAF system running version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, 13.1.0-13.1.3.4, 12.1.0-12.1.5.2, or 11.6.1-11.6.5.2 processes requests with JSON payload, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process.

Affected products

• F5 BIG-IP Advanced Web Application Firewall: from 11.6.1, up to and including 11.6.5; from 12.1.0, up to and including 12.1.5; from 13.1.0, before 13.1.3.5 (fixed in 13.1.3.5); from 14.1.0, before 14.1.3.1 (fixed in 14.1.3.1); from 15.0.0, before 15.1.1 (fixed in 15.1.1); from 16.0.0, before 16.0.1 (fixed in 16.0.1)
• F5 BIG-IP Application Security Manager: from 11.6.1, up to and including 11.6.5; from 12.1.0, up to and including 12.1.5; from 13.1.0, before 13.1.3.5 (fixed in 13.1.3.5); from 14.1.0, before 14.1.3.1 (fixed in 14.1.3.1); from 15.0.0, before 15.1.1 (fixed in 15.1.1); from 16.0.0, before 16.0.1 (fixed in 16.0.1)

Published 2020-12-24. Last modified 2026-06-17.