Traffic Management Microkernel Vulnerability in F5 BIG-IP DNS
CVE-2026-39458

8.7HIGH

Key Information:

Vendor

F5
Status
Big-ip
Vendor
CVE Published:
13 May 2026

What is CVE-2026-39458?

A vulnerability exists in F5 BIG-IP DNS when a DNS profile with caching is set on a virtual server. This flaw may allow undisclosed traffic to disrupt the functioning of the Traffic Management Microkernel (TMM), potentially leading to service outages. It is important to review your version's support status, as software versions that have reached End of Technical Support (EoTS) are excluded from this evaluation.

Affected Version(s)

BIG-IP 21.0.0 < 21.0.0.1

BIG-IP 17.5.0 < 17.5.1.6

BIG-IP 17.1.0 < 17.1.3.2

References

https://my.f5.com/manage/s/article/K000160945
vendor-advisorypatch

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

F5
.