CVE-2021-1352: Cisco IOS XE

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability in the DECnet Phase IV and DECnet/OSI protocol processing of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to insufficient input validation of DECnet traffic that is received by an affected device. An attacker could exploit this vulnerability by sending DECnet traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Affected products

• Cisco IOS XE: version 16.4.1 only; version 16.4.2 only; version 16.4.3 only; version 16.5.1 only; version 16.5.1a only; version 16.5.1b only; …

Published 2021-03-24. Last modified 2026-06-17.