CVE-2021-1390
A vulnerability in one of the diagnostic test CLI commands of Cisco IOS XE Software could allow an authenticated, local attacker to execute arbitrary code on an affected device. To exploit this vulnerability, the attacker would need to have valid user credentials at privilege level 15. This vulnerability exists because the affected software permits modification of the run-time memory of an affected device under specific circumstances. An attacker could exploit this vulnerability by authenticating to the affected device and issuing a specific diagnostic test command at the CLI. A successful exploit could trigger a logic error in the code that was designed to restrict run-time memory modifications. The attacker could take advantage of this logic error to overwrite system memory locations and execute arbitrary code on the underlying Linux operating system (OS) of the affected device.
Source: CVE-2021-1390