# What is CVE-2020-27128? > CVE-2020-27128 is a medium-severity flaw (CVSS 6.5) in SD-WAN from Cisco, published on 6 November 2020. 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 61%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-27128 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 48 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 6.5 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:** 61% (latest exploit-likelihood forecast) - **Published:** 6 November 2020 - **Record last updated:** 7 November 2023 - **Main product:** SD-WAN from Cisco - **Affected products:** 1 ## What is CVE-2020-27128? In plain terms It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can change data. ### The official description A vulnerability in the application data endpoints of Cisco SD-WAN vManage Software could allow an authenticated, remote attacker to write arbitrary files to an affected system. The vulnerability is due to improper validation of requests to APIs. An attacker could exploit this vulnerability by sending malicious requests to an API within the affected application. A successful exploit could allow the attacker to conduct directory traversal attacks and write files to an arbitrary location on the targeted system. ### What kind of flaw is it? - CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') ### 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: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can change data Severity vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N` ## Is CVE-2020-27128 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 61%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 61%, 61%, 61%, 61%, 61%, 61%, 61%. ### Timeline - 6 November 2020: Published - 7 November 2023: Record last updated - 16 June 2026: Exploit likelihood jumped ### How Precursor Intelligence ranks it CVE-2020-27128 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-2020-27128? The published record lists 1 product. Versions are as published: "before 20.3.1" means every version up to, but not including, 20.3.1. - [SD-WAN](https://www.precursorintelligence.com/product/cisco/sd-wan) by [Cisco](https://www.precursorintelligence.com/vendors/cisco) (Application): before 20.3.1 ## How do I fix CVE-2020-27128? 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-vmanage-file-Y2JSRNRb) (Vendor advisory) ## Questions ### What is CVE-2020-27128? CVE-2020-27128 is a medium-severity flaw in SD-WAN from Cisco, published on 6 November 2020. It can be attacked from anywhere on the internet with an ordinary user account, and nobody has to click anything. If it works, the attacker can change data. ### How serious is CVE-2020-27128? It scores 6.5 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2020-27128 is 48 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2020-27128 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 61%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2020-27128 affect? For SD-WAN from Cisco: before 20.3.1. ### How do I fix CVE-2020-27128? 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-2020-27128 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