CVE-2021-22976

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-02-12 · updated 2026-06-17

Description

On BIG-IP Advanced WAF and ASM version 16.0.x before 16.0.1.1, 15.1.x before 15.1.2, 14.1.x before 14.1.3.1, 13.1.x before 13.1.3.6, and all 12.1.x versions, when the BIG-IP ASM system processes WebSocket requests with JSON payloads, an unusually large number of parameters can cause excessive CPU usage in the BIG-IP ASM bd process. Note: Software versions which have reached End of Software Development (EoSD) are not evaluated.

Affected products

F5 Big-Ip Advanced Web Application Firewall: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.3.1; from 15.1.0 before 15.1.2; from 16.0.0 before 16.0.1.1 — fixed in 13.1.3.6, 14.1.3.1, 15.1.2, 16.0.1.1
BIG-IP ASM: from 12.1.0 through 12.1.5; from 13.1.0 before 13.1.3.6; from 14.1.0 before 14.1.3.1; from 15.1.0 before 15.1.2; from 16.0.0 before 16.0.1.1 — fixed in 13.1.3.6, 14.1.3.1, 15.1.2, 16.0.1.1

How to fix

Upgrade to a fixed version: F5 Big-Ip Advanced Web Application Firewall 13.1.3.6, 14.1.3.1, 15.1.2, 16.0.1.1; BIG-IP ASM 13.1.3.6, 14.1.3.1, 15.1.2, 16.0.1.1. Check the vendor advisory for mitigations.

References

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