CVE-2021-1523

Cisco Nexus 9000 Series Fabric Switches ACI Mode Queue Wedge Denial of Service Vulnerability

Description

A vulnerability in Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) Mode could allow an unauthenticated, remote attacker to cause a queue wedge on a leaf switch, which could result in critical control plane traffic to the device being dropped. This could result in one or more leaf switches being removed from the fabric. This vulnerability is due to mishandling of ingress TCP traffic to a specific port. An attacker could exploit this vulnerability by sending a stream of TCP packets to a specific port on a Switched Virtual Interface (SVI) configured on the device. A successful exploit could allow the attacker to cause a specific packet queue to queue network buffers but never process them, leading to an eventual queue wedge. This could cause control plane traffic to be dropped, resulting in a denial of service (DoS) condition where the leaf switches are unavailable. Note: This vulnerability requires a manual intervention to power-cycle the device to recover.

Category

8.6
CVSS
Severity: High
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.54%
Vendor Advisory cisco.com
Affected: Cisco Cisco NX-OS System Software in ACI Mode
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-1523?
CVE-2021-1523 has been scored as a high severity vulnerability.
How to fix CVE-2021-1523?
To fix CVE-2021-1523, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-1523 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-1523 is being actively exploited. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-1523?
CVE-2021-1523 affects Cisco Cisco NX-OS System Software in ACI Mode.
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