CVE-2021-23034

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 version 16.x before 16.1.0 and 15.1.x before 15.1.3.1, when a DNS profile using a DNS cache resolver is configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) process to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Affected products

F5 BIG-IP APM: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
BIG-IP: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Big-Ip Analytics: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Networks, Inc. BIG-IP (AAM): from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
BIG-IP ASM: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 BIG-IP DNS: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Big-Ip Fraud Protection Service: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Big-Ip Global Traffic Manager: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Big-Ip Link Controller: from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 BIG-IP (LTM): from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0
F5 Networks, Inc. BIG-IP (PEM): from 15.1.0 before 15.1.3.1; from 16.0.0 before 16.1.0 — fixed in 15.1.3.1, 16.1.0

How to fix

Upgrade to a fixed version: F5 BIG-IP APM 15.1.3.1, 16.1.0; BIG-IP 15.1.3.1, 16.1.0; F5 Big-Ip Analytics 15.1.3.1, 16.1.0; F5 Networks, Inc. BIG-IP (AAM) 15.1.3.1, 16.1.0; BIG-IP ASM 15.1.3.1, 16.1.0; F5 BIG-IP DNS 15.1.3.1, 16.1.0; F5 Big-Ip Fraud Protection Service 15.1.3.1, 16.1.0; F5 Big-Ip Global Traffic Manager 15.1.3.1, 16.1.0; F5 Big-Ip Link Controller 15.1.3.1, 16.1.0; F5 BIG-IP (LTM) 15.1.3.1, 16.1.0; F5 Networks, Inc. BIG-IP (PEM) 15.1.3.1, 16.1.0. Check the vendor advisory for mitigations.

References

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