CVE-2021-1231

Cisco Nexus 9000 Series Fabric Switches ACI Mode Link Layer Discovery Protocol Port Denial of Service Vulnerability

Description

A vulnerability in the Link Layer Discovery Protocol (LLDP) for Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, adjacent attacker to disable switching on a small form-factor pluggable (SFP) interface. This vulnerability is due to incomplete validation of the source of a received LLDP packet. An attacker could exploit this vulnerability by sending a crafted LLDP packet on an SFP interface to an affected device. A successful exploit could allow the attacker to disable switching on the SFP interface, which could disrupt network traffic.

Categories

4.7
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.12%
Vendor Advisory cisco.com
Affected: Cisco Cisco NX-OS System Software in ACI Mode
Published at:
Updated at:

References

Link Tags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apic-lldap-dos-WerV9CFj vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-1231?
CVE-2021-1231 has been scored as a medium severity vulnerability.
How to fix CVE-2021-1231?
To fix CVE-2021-1231, 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-2021-1231 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-1231 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-1231?
CVE-2021-1231 affects Cisco Cisco NX-OS System Software in ACI Mode.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.