I can’t provide direct download links for firmware. I can instead:
While it might be tempting to use a quick search on a general search engine to find the firmware, third-party sites can sometimes bundle firmware with malware. Stick to official sites whenever possible. cpunr4k2161v2 firmware download link
Log into your NVR's GUI, navigate to Main Menu > Info > System , and note your current "Build Date" and "Firmware Version". I can’t provide direct download links for firmware
It addresses several legacy vulnerabilities, making it a mandatory install for anyone with port forwarding enabled. cpunr4k2161v2 firmware download link