Last Modified: Oct 06, 2026
Affected Product(s):
BIG-IP TMOS
Known Affected Versions:
17.1.3.4, 17.1.3.5, 17.5.1.8, 17.5.1.9, 21.1.0.1, 21.1.0.2
Opened: Jul 30, 2026 Severity: 3-Major
When a Virtual Server name contains a colon character (for example, /Common/1.1.1.1:124), clicking on it in the TMUI displays "Instance not found" and the properties page fails to load, even though the object exists in the configuration and the backend returns an HTTP 200 OK response
Objects whose names contain a colon can be created and configured via tmsh, but cannot be viewed or managed through the TMUI GUI. Users attempting to access the properties, resources, or statistics pages for such objects are blocked with an "Instance not found" error, preventing GUI-based administration of these objects
This occurs when an LTM object (such as a virtual server) is named using the <address>:<port> convention, which includes a colon character — for example, a virtual server created via tmsh create ltm virtual /Common/1.1.1.1:124 destination 1.1.1.1:124. Navigating to that object's properties page in the TMUI (e.g., Local Traffic > Virtual Servers) triggers the issue
Manage affected objects (those with a colon in the name) via tmsh or the REST API instead of the TMUI, until the fix is applied
None