Last Modified: Dec 16, 2025
Affected Product(s):
BIG-IP AFM, APM, ASM, AVR, DNS, GTM, Install/Upgrade, LTM, TMOS
Known Affected Versions:
21.0.0
Opened: Nov 06, 2025 Severity: 1-Blocking
On affected versions of BIG-IP, if the BIG-IP software ISO file signature checking feature is enabled, attempting to install any BIG-IP version will fail. Attempting to install the BIG-IP image using either tmsh or the GUI will result in the following error messages (as shown by the "tmsh show /sys software status" command, or hovering a mouse over the "Failed" Install Status message in the GUI): failed (Signature verification failed - no sig file found)
It is not possible to install any BIG-IP version with the BIG-IP software ISO file signature checking feature enabled.
This occurs on affected versions if the BIG-IP software ISO file signature checking feature is enabled, as described in the following article: K15225: Enabling signature verification for BIG-IP and BIG-IQ ISO image files https://my.f5.com/manage/s/article/K15225
To successfully install the desired BIG-IP version in such cases: 1. Disable ISO Signature Verification 2. Install the desired BIG-IP version 3. Re-enable ISO Signature Verification
None