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 s…

published 2021-09-14 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10152

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.9%; EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits: 0; none known

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.

Patch / fix

fixed in 11

f5 big-ip_access_policy_manager 15.1.3.1, 16.1.0
f5 big-ip_advanced_firewall_manager 15.1.3.1, 16.1.0
f5 big-ip_analytics 15.1.3.1, 16.1.0
f5 big-ip_application_acceleration_manager 15.1.3.1, 16.1.0
f5 big-ip_application_security_manager 15.1.3.1, 16.1.0
f5 big-ip_domain_name_system 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_local_traffic_manager 15.1.3.1, 16.1.0
f5 big-ip_policy_enforcement_manager 15.1.3.1, 16.1.0

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	7.1	AV:N/AC:M/Au:N/C:N/I:N/A:C

Affected products

n/a BIG-IP

Classification

Weakness

CWE-20 Improper Input Validation
CWE-668 Exposure of Resource to Wrong Sphere

References

support.f5.com /csp/article/K30523121
vendor-advisory

Sources

CVE List CVE-2021-23034
NVD CVE-2021-23034

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Summary