This identifier refers to a specific technical issue tracked by Cisco:
While the number matches a known Cisco software bug, .rar files with generic numeric names (like 21398.rar) are frequently used on third-party file-sharing sites to distribute potentially harmful content or cracked software. 21398.rar
Release Notes for StarOS™ Software Version 21.23.5 - Cisco This identifier refers to a specific technical issue
: The bug involved a task restart (crash) occurring when a configuration was applied to the User Plane (UP) #01. : It affected the Control and User Plane
: Technical patches for hardware like the ASR 5000 should only be obtained directly from the Cisco Software Download portal to ensure authenticity.
: It affected the Control and User Plane Separation (CUPS) architecture within the StarOS operating system used on Cisco ASR 5000 series routers.
: A fix for this task restart issue was included in StarOS Software Version 21.23.5 , released in July 2021. Safety and File Verification