CVE-2021-1591
5.8 · MEDIUMA vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are co…
Overview
CVE-2021-1591 is a medium-severity vulnerability. It was published on August 25, 2021 and has a CVSS 3.1 base score of 5.8 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.8, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical description
A vulnerability in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches could allow an unauthenticated, remote attacker to bypass access control list (ACL) rules that are configured on an affected device. This vulnerability is due to oversubscription of resources that occurs when applying ACLs to port channel interfaces. An attacker could exploit this vulnerability by attempting to access network resources that are protected by the ACL. A successful exploit could allow the attacker to access network resources that would be protected by the ACL that was applied on the port channel interface.
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
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Frequently asked questions
What is CVE-2021-1591?
CVE-2021-1591 is a medium-severity vulnerability. It was published on August 25, 2021 and has a CVSS 3.1 base score of 5.8 (MEDIUM).
How severe is CVE-2021-1591?
This vulnerability has a CVSS 3.1 base score of 5.8, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-1591?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-1591?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-1591 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.
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