CVE-2021-23039

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 version 16.0.x before 16.0.1.2, 15.1.x before 15.1.3, 14.1.x before 14.1.2.8, and all versions of 13.1.x and 12.1.x, when IPSec is configured on a BIG-IP system, undisclosed requests from an authorized remote (IPSec) peer, which already has a negotiated Security Association, can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

F5 BIG-IP APM: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
BIG-IP: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Big-Ip Analytics: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Networks, Inc. BIG-IP (AAM): from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
BIG-IP ASM: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 BIG-IP DNS: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Big-Ip Fraud Protection Service: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Big-Ip Global Traffic Manager: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Big-Ip Link Controller: from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 BIG-IP (LTM): from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2
F5 Networks, Inc. BIG-IP (PEM): from 12.1.0 through 12.1.6; from 13.1.0 through 13.1.4; from 14.1.0 before 14.1.2.8; from 15.1.0 before 15.1.3; from 16.0.0 before 16.0.1.2 — fixed in 14.1.2.8, 15.1.3, 16.0.1.2

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 14.1.2.8, 15.1.3, 16.0.1.2; BIG-IP 14.1.2.8, 15.1.3, 16.0.1.2; F5 Big-Ip Analytics 14.1.2.8, 15.1.3, 16.0.1.2; F5 Networks, Inc. BIG-IP (AAM) 14.1.2.8, 15.1.3, 16.0.1.2; BIG-IP ASM 14.1.2.8, 15.1.3, 16.0.1.2; F5 BIG-IP DNS 14.1.2.8, 15.1.3, 16.0.1.2; F5 Big-Ip Fraud Protection Service 14.1.2.8, 15.1.3, 16.0.1.2; F5 Big-Ip Global Traffic Manager 14.1.2.8, 15.1.3, 16.0.1.2; F5 Big-Ip Link Controller 14.1.2.8, 15.1.3, 16.0.1.2; F5 BIG-IP (LTM) 14.1.2.8, 15.1.3, 16.0.1.2; F5 Networks, Inc. BIG-IP (PEM) 14.1.2.8, 15.1.3, 16.0.1.2. Check the vendor advisory for mitigations.

References

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