A vulnerability in the IPv4 protocol handling of Cisco StarOS could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.
The vulnerability is due to a memory leak that occurs during packet processing. An attacker could exploit this vulnerability by sending a series of crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to exhaust the available memory and cause an unexpected restart of the npusim process, leading to a DoS condition on the affected device.

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-1353
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr-mem-leak-dos-MTWGHKk3