F5 BIGIP TMM Crash via DNS Cache on Virtual Server
CVE-2026-39458 Published on May 13, 2026
BIG-IP DNS Cache vulnerability
When a BIG-IP DNS profile enabled with DNS cache is configured on a virtual server, undisclosed traffic can cause the Traffic Management Microkernel (TMM) to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Vulnerability Analysis
CVE-2026-39458 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
Access of Uninitialized Pointer
The program accesses or uses a pointer that has not been initialized.
Products Associated with CVE-2026-39458
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Affected Versions
F5 BIG-IP:- Version 21.1.0 and below * is unaffected.
- Version 21.0.0 and below 21.0.0.1 is affected.
- Version 17.5.0 and below 17.5.1.6 is affected.
- Version 17.1.0 and below 17.1.3.2 is affected.
- Version 16.1.0 and below * is affected.