# What is CVE-2021-1230? > CVE-2021-1230 is a high-severity flaw (CVSS 7.5) in NX-OS from Cisco, published on 24 February 2021. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 1.5%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-1230 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 48 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.5 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 1.5% (latest exploit-likelihood forecast) - **Published:** 24 February 2021 - **Record last updated:** 7 November 2023 - **Main product:** NX-OS from Cisco - **Affected products:** 41 ## What is CVE-2021-1230? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### The official 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. ### What kind of flaw is it? - CWE-233: Improper Handling of Parameters ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` ## Is CVE-2021-1230 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.5%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 1.5%, 1.5%, 1.5%, 1.5%, 1.5%, 1.5%, 1.5%. ### Timeline - 24 February 2021: Published - 7 November 2023: Record last updated ### How Precursor Intelligence ranks it CVE-2021-1230 scores **48 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2021-1230? The published record lists 41 products. - [NX-OS](https://www.precursorintelligence.com/product/cisco/nx-os) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Operating system): 12.0(1m), 12.0(1n), 12.0(1o), 12.0(1p), 12.0(1q), 12.0(1r), 12.0(2f), 12.0(2g), 12.0(2h), 12.0(2l), 12.0(2m), 12.0(2n), 12.0(2o), 12.1(1h), 12.1(1i), 12.1(2e), 12.1(2g), 12.1(2k), 12.1(3g), 12.1(3h), 12.1(3j), 12.1(4a), 12.2(1k), 12.2(1n), 12.2(1o), 12.2(2e), 12.2(2f), 12.2(2i), 12.2(2j), 12.2(2k), 12.2(2q), 12.2(3j), 12.2(3p), 12.2(3r), 12.2(3s), 12.2(3t), 12.2(4f), 12.2(4p), 12.2(4q), 12.2(4r) and 63 more - [Nexus 9000v](https://www.precursorintelligence.com/product/cisco/nexus_9000v) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 92160yc-X](https://www.precursorintelligence.com/product/cisco/nexus_92160yc-x) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 92300yc](https://www.precursorintelligence.com/product/cisco/nexus_92300yc) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 92304qc](https://www.precursorintelligence.com/product/cisco/nexus_92304qc) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 92348gc-X](https://www.precursorintelligence.com/product/cisco/nexus_92348gc-x) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9236c](https://www.precursorintelligence.com/product/cisco/nexus_9236c) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9272q](https://www.precursorintelligence.com/product/cisco/nexus_9272q) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93108tc-EX](https://www.precursorintelligence.com/product/cisco/nexus_93108tc-ex) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93108tc-EX-24](https://www.precursorintelligence.com/product/cisco/nexus_93108tc-ex-24) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93108tc-Fx](https://www.precursorintelligence.com/product/cisco/nexus_93108tc-fx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93108tc-Fx-24](https://www.precursorintelligence.com/product/cisco/nexus_93108tc-fx-24) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93120tx](https://www.precursorintelligence.com/product/cisco/nexus_93120tx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93128tx](https://www.precursorintelligence.com/product/cisco/nexus_93128tx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9316d-Gx](https://www.precursorintelligence.com/product/cisco/nexus_9316d-gx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180lc-EX](https://www.precursorintelligence.com/product/cisco/nexus_93180lc-ex) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-EX](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-ex) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-EX-24](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-ex-24) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-Fx](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-fx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-Fx-24](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-fx-24) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-Fx3](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-fx3) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93180yc-Fx3s](https://www.precursorintelligence.com/product/cisco/nexus_93180yc-fx3s) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93216tc-Fx2](https://www.precursorintelligence.com/product/cisco/nexus_93216tc-fx2) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93240yc-Fx2](https://www.precursorintelligence.com/product/cisco/nexus_93240yc-fx2) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9332c](https://www.precursorintelligence.com/product/cisco/nexus_9332c) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9332pq](https://www.precursorintelligence.com/product/cisco/nexus_9332pq) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93360yc-Fx2](https://www.precursorintelligence.com/product/cisco/nexus_93360yc-fx2) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9336c-Fx2](https://www.precursorintelligence.com/product/cisco/nexus_9336c-fx2) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9336c-Fx2-E](https://www.precursorintelligence.com/product/cisco/nexus_9336c-fx2-e) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9336pq ACI Spine](https://www.precursorintelligence.com/product/cisco/nexus_9336pq_aci_spine) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9348gc-Fxp](https://www.precursorintelligence.com/product/cisco/nexus_9348gc-fxp) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 93600cd-Gx](https://www.precursorintelligence.com/product/cisco/nexus_93600cd-gx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9364c](https://www.precursorintelligence.com/product/cisco/nexus_9364c) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9364c-Gx](https://www.precursorintelligence.com/product/cisco/nexus_9364c-gx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9372px](https://www.precursorintelligence.com/product/cisco/nexus_9372px) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9372px-E](https://www.precursorintelligence.com/product/cisco/nexus_9372px-e) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9372tx](https://www.precursorintelligence.com/product/cisco/nexus_9372tx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9372tx-E](https://www.precursorintelligence.com/product/cisco/nexus_9372tx-e) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9396px](https://www.precursorintelligence.com/product/cisco/nexus_9396px) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9396tx](https://www.precursorintelligence.com/product/cisco/nexus_9396tx) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified - [Nexus 9508](https://www.precursorintelligence.com/product/cisco/nexus_9508) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Hardware): version not specified ## How do I fix CVE-2021-1230? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [tools.cisco.com](https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-n9kaci-bgp-De9dPKSK) (Vendor advisory) ## Questions ### What is CVE-2021-1230? CVE-2021-1230 is a high-severity flaw in NX-OS from Cisco, published on 24 February 2021. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can take it offline. ### How serious is CVE-2021-1230? It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-1230 is 48 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2021-1230 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 1.5%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2021-1230 affect? For NX-OS from Cisco: 12.0(1m), 12.0(1n), 12.0(1o), 12.0(1p), 12.0(1q), 12.0(1r) and 97 more. The record lists 41 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2021-1230? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2021-1230 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact