# What is CVE-2021-20160? > CVE-2021-20160 is a high-severity flaw (CVSS 8.8) in Tew-827dru from Trendnet, published on 30 December 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 3.1%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-20160 ## 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:** 58 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 8.8 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:** 3.1% (latest exploit-likelihood forecast) - **Published:** 30 December 2021 - **Record last updated:** 12 July 2022 - **Main product:** Tew-827dru from Trendnet - **Affected products:** 2 ## What is CVE-2021-20160? 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 read data, change data and take it offline. ### The official description Trendnet AC2600 TEW-827DRU version 2.08B01 contains a command injection vulnerability in the smb functionality of the device. The username parameter used when configuring smb functionality for the device is vulnerable to command injection as root. ### What kind of flaw is it? - CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') ### 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 read data, change data and take it offline Severity vector: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` ## Is CVE-2021-20160 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 3.1%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 3.1%, 3.1%, 3.1%, 3.1%, 3.1%, 3.1%, 3.1%. ### Timeline - 30 December 2021: Published - 12 July 2022: Record last updated ### How Precursor Intelligence ranks it CVE-2021-20160 scores **58 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: key context - Real threat activity around it: key context 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-2021-20160? The published record lists 2 products. - [Tew-827dru](https://www.precursorintelligence.com/product/trendnet/tew-827dru) by [Trendnet](https://www.precursorintelligence.com/vendors/trendnet) (Hardware): 2.0 - [Tew-827dru Firmware](https://www.precursorintelligence.com/product/trendnet/tew-827dru_firmware) by [Trendnet](https://www.precursorintelligence.com/vendors/trendnet) (Operating system): 2.08b01 ## How do I fix CVE-2021-20160? 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 latest update from the vendor. The references list where the vendor has published details. 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 - [tenable.com](https://www.tenable.com/security/research/tra-2021-54) (Exploit, Third-party advisory) ## Questions ### What is CVE-2021-20160? CVE-2021-20160 is a high-severity flaw in Tew-827dru from Trendnet, published on 30 December 2021. 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 read data, change data and take it offline. ### How serious is CVE-2021-20160? It scores 8.8 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-20160 is 58 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-2021-20160 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 3.1%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2021-20160 affect? For Tew-827dru from Trendnet: 2.0. The record lists 2 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2021-20160? Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2021-20160 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