CVE-2021-1230: A vulnerability with the Border Gateway Protocol (BGP) for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode co...

Description

A vulnerability with the Border Gateway Protocol (BGP) for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a routing process to crash, which could lead to a denial of service (DoS) condition. This vulnerability is due to an issue with the installation of routes upon receipt of a BGP update. An attacker could exploit this vulnerability by sending a crafted BGP update to an affected device. A successful exploit could allow the attacker to cause the routing process to crash, which could cause the device to reload. This vulnerability applies to both Internal BGP (IBGP) and External BGP (EBGP). Note: The Cisco implementation of BGP accepts incoming BGP traffic from explicitly configured peers only. To exploit this vulnerability, an attacker would need to send a specific BGP update message over an established TCP connection that appears to come from a trusted BGP peer.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.48%

70.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-233

Affected Software

Vendor	Product	Versions
Cisco	Nx-Os	12.0\(1m\)
Cisco	Nx-Os	12.0\(1n\)
Cisco	Nx-Os	12.0\(1o\)
Cisco	Nx-Os	12.0\(1p\)
Cisco	Nx-Os	12.0\(1q\)
Cisco	Nx-Os	12.0\(1r\)
Cisco	Nx-Os	12.0\(2f\)
Cisco	Nx-Os	12.0\(2g\)
Cisco	Nx-Os	12.0\(2h\)
Cisco	Nx-Os	12.0\(2l\)
Cisco	Nx-Os	12.0\(2m\)
Cisco	Nx-Os	12.0\(2n\)
Cisco	Nx-Os	12.0\(2o\)
Cisco	Nx-Os	12.1\(1h\)
Cisco	Nx-Os	12.1\(1i\)
Cisco	Nx-Os	12.1\(2e\)
Cisco	Nx-Os	12.1\(2g\)
Cisco	Nx-Os	12.1\(2k\)
Cisco	Nx-Os	12.1\(3g\)
Cisco	Nx-Os	12.1\(3h\)
Cisco	Nx-Os	12.1\(3j\)
Cisco	Nx-Os	12.1\(4a\)
Cisco	Nx-Os	12.2\(1k\)
Cisco	Nx-Os	12.2\(1n\)
Cisco	Nx-Os	12.2\(1o\)
Cisco	Nx-Os	12.2\(2e\)
Cisco	Nx-Os	12.2\(2f\)
Cisco	Nx-Os	12.2\(2i\)
Cisco	Nx-Os	12.2\(2j\)
Cisco	Nx-Os	12.2\(2k\)
Cisco	Nx-Os	12.2\(2q\)
Cisco	Nx-Os	12.2\(3j\)
Cisco	Nx-Os	12.2\(3p\)
Cisco	Nx-Os	12.2\(3r\)
Cisco	Nx-Os	12.2\(3s\)
Cisco	Nx-Os	12.2\(3t\)
Cisco	Nx-Os	12.2\(4f\)
Cisco	Nx-Os	12.2\(4p\)
Cisco	Nx-Os	12.2\(4q\)
Cisco	Nx-Os	12.2\(4r\)
Cisco	Nx-Os	12.3\(1e\)
Cisco	Nx-Os	12.3\(1f\)
Cisco	Nx-Os	12.3\(1i\)
Cisco	Nx-Os	12.3\(1l\)
Cisco	Nx-Os	12.3\(1o\)
Cisco	Nx-Os	12.3\(1p\)
Cisco	Nx-Os	13.0\(1k\)
Cisco	Nx-Os	13.0\(2h\)
Cisco	Nx-Os	13.0\(2k\)
Cisco	Nx-Os	13.0\(2n\)

Showing 50 of 103 affected configurations. See NVD for the full list.

References

Timeline

Published: Feb 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-1230?

A vulnerability with the Border Gateway Protocol (BGP) for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a routing process to crash, which could lead to a denial of service (DoS) condition. This vulnerability is due to an issue with the installation of routes upon receipt of a BGP update. An attacker could exploit this vulnerability by sending a crafted BGP update to an affected device. A successful exploit could allow the attacker to cause the routing process to crash, which could cause the device to reload. This vulnerability applies to both Internal BGP (IBGP) and External BGP (EBGP). Note: The Cisco implementation of BGP accepts incoming BGP traffic from explicitly configured peers only. To exploit this vulnerability, an attacker would need to send a specific BGP update message over an established TCP connection that appears to come from a trusted BGP peer.

How severe is CVE-2021-1230?

CVE-2021-1230 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.48% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1230?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.