CVE-2021-34697

A vulnerability in the Protection Against Distributed Denial of Service Attacks feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct denial of service (DoS) attacks to or through the affected device. This vulnerability is due to incorrect programming of the half-opened connections limit, TCP SYN flood limit, or TCP SYN cookie features when the features are configured in vulnerable releases of Cisco IOS XE Software. An attacker could exploit this vulnerability by attempting to flood traffic to or through the affected device. A successful exploit could allow the attacker to initiate a DoS attack to or through an affected device.

• CWE-665
• CWE-665

• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-tguGuYqVendor Advisory
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-tguGuYqVendor Advisory

Published

Sep 23, 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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