CVE-2021-23033

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-09-14 · updated 2026-06-17
Weakness: CWE-20

Description

On BIG-IP Advanced WAF and BIG-IP ASM version 16.x before 16.1.0x, 15.1.x before 15.1.3.1, 14.1.x before 14.1.4.3, 13.1.x before 13.1.4.1, and all versions of 12.1.x, when a WebSocket profile is configured on a virtual server, undisclosed requests can cause bd to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

F5 Big-Ip Advanced Web Application Firewall: from 12.1.0 through 12.1.6; from 13.1.0 before 13.1.4.1; from 14.1.0 before 14.1.4.3; from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 13.1.4.1, 14.1.4.3, 15.1.3.1, 16.1.0
BIG-IP ASM: from 12.1.0 through 12.1.6; from 13.1.0 before 13.1.4.1; from 14.1.0 before 14.1.4.3; from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 13.1.4.1, 14.1.4.3, 15.1.3.1, 16.1.0

How to fix

Upgrade to a fixed version: F5 Big-Ip Advanced Web Application Firewall 13.1.4.1, 14.1.4.3, 15.1.3.1, 16.1.0; BIG-IP ASM 13.1.4.1, 14.1.4.3, 15.1.3.1, 16.1.0. Check the vendor advisory for mitigations.

References

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