CVE-2021-1591: Cisco Nexus 9500 Series Switches Access Control List Bypass Vulnerability
First published: Wed Aug 25 2021(Updated: )
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.
Credit: ykramarz@cisco.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cisco Nx-os | =9.3\(4\) | |
| Cisco Nexus 9500 16-slot | ||
| Cisco Nexus 9500 4-slot | ||
| Cisco Nexus 9500 8-slot | ||
| Cisco Nexus 9504 | ||
| Cisco Nexus 9508 | ||
| Cisco Nexus 9516 |
Remedy
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nexus-acl-vrvQYPVe
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Reference Links
Frequently Asked Questions
What is the vulnerability ID?
The vulnerability ID is CVE-2021-1591.
What is the severity of CVE-2021-1591?
The severity of CVE-2021-1591 is medium.
How does CVE-2021-1591 affect Cisco Nexus 9500 Series Switches?
CVE-2021-1591 allows an unauthenticated, remote attacker to bypass access control list (ACL) rules configured on affected Cisco Nexus 9500 Series Switches.
What is the cause of CVE-2021-1591?
CVE-2021-1591 is caused by oversubscription of resources in the EtherChannel port subscription logic of Cisco Nexus 9500 Series Switches.
Is there a fix for CVE-2021-1591?
Yes, Cisco has provided a fix for CVE-2021-1591. Please refer to the Cisco Security Advisory for more information.
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- agent/weakness
- agent/last-modified-date
- agent/description
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- agent/event
- agent/tags
- vendor/cisco
- canonical/cisco nx-os
- version/cisco nx-os/9.3\(4\)
- canonical/cisco nexus 9500 16-slot
- canonical/cisco nexus 9500 4-slot
- canonical/cisco nexus 9500 8-slot
- canonical/cisco nexus 9504
- canonical/cisco nexus 9508
- canonical/cisco nexus 9516