CVE-2021-1377

A vulnerability in Address Resolution Protocol (ARP) management of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to prevent an affected device from resolving ARP entries for legitimate hosts on the connected subnets. This vulnerability exists because ARP entries are mismanaged. An attacker could exploit this vulnerability by continuously sending traffic that results in incomplete ARP entries. A successful exploit could allow the attacker to cause ARP requests on the device to be unsuccessful for legitimate hosts, resulting in a denial of service (DoS) condition.

• CWE-399

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-arp-mtfhBfjEVendor Advisory
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-arp-mtfhBfjEVendor Advisory

Published

Mar 24, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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