How severe is CVE-2021-1230?

CVE-2021-1230 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-1230 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-1230?

CVE-2021-1230 primarily affects Cisco Nx-os. In total, 103 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-1230?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-1230 published?

CVE-2021-1230 was published on 2021-02-24 and last updated on 2026-06-17.

CVE-2021-1230

CVE-2021-1230 is a high-severity vulnerability in Cisco Nx-os with a CVSS 3.x base score of 8.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-233.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v2: 7.1
EPSS exploit prediction: 1% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-233
Affected product: Cisco Nx-os
Published: 2021-02-24
Last modified: 2026-06-17

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.

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 3.x base score of 8.6, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-1230 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1230?: CVE-2021-1230 primarily affects Cisco Nx-os. In total, 103 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1230?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-1230 published?: CVE-2021-1230 was published on 2021-02-24 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9kaci-bgp-De9dPKSK

Affected products (103)

cpe:2.3:o:cisco:nx-os:12.0\(1m\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(1n\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(1o\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(1p\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(1q\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(1r\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2f\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2g\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2h\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2l\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2m\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2n\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.0\(2o\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(1h\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(1i\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(2e\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(2g\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(2k\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(3g\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(3h\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(3j\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.1\(4a\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(1k\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(1n\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(1o\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2e\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2f\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2i\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2j\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2k\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(2q\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(3j\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(3p\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(3r\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(3s\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(3t\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(4f\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(4p\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(4q\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:nx-os:12.2\(4r\):*:*:*:*:*:*:*

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