Last Modified: Jun 17, 2026
Affected Product(s):
BIG-IP F5OS-A, F5OS-C
Known Affected Versions:
17.1.3, 17.1.3.1, 17.1.3.2, 17.5.0, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6
Opened: May 01, 2026 Severity: 3-Major
On F5OS, the masquerade MAC remains active after loading a UCS file when the system enters standby mode.
Connectivity issues due to the maquerade MAc being present on the standby system.
-- BIG-IP running on F5OS in an HA pair. -- A UCS file is loaded that creates static L2 entries for a MAC masquerade address. -- The system fails over and becomes standby.
Make the tenant active again, then fail over again.
None