CVE-2021-34697

    Dashboard / Vulnerabilities / CVE-2021-34697

    CVE-2021-34697

    Published: 23 Sept 2021Last Modified: 10 Mar 2026

    Summary:

    Details: 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.

    References: , https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-zbfw-tguGuYq

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: N/A

    Events:

    Introduced- None
    Fixed -None

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    CVE-2021-34697 | CVE-DB