What is CVE-2021-20161?

CVE-2021-20161 is a medium-severity vulnerability in Trendnet Tew-827dru, classified under Improper Authentication. CVSS score: 6.8/10. Published 2021-12-30.

How severe is CVE-2021-20161?

Medium severity. CVSS v3 base score is 6.8 out of 10.

Auth bypass in Trendnet Tew-827dru

CVE-2021-20161

Trendnet AC2600 TEW-827DRU version 2.08B01 does not have sufficient protections for the UART functionality. A malicious actor with physical access to the device is able to connect to the UART port via a serial connection. No username or password is required and the user is given a root shell with full control of the device.

Vulnerability class: Broken Authentication

Published 2021-12-30 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.002 (14.6th percentile), scored 2026-10-07.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 14.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Trendnet Tew-827dru — versions 2.0
Trendnet Tew-827dru Firmware — versions 2.08b01
Trendnet Ac2600 Tew-827dru — versions 2.08B01

Weakness classification (CWE)

References

www.tenable.com/security/research/tra-2021-54 (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20161?: CVE-2021-20161 is a medium-severity vulnerability in Trendnet Tew-827dru, classified under Improper Authentication. CVSS score: 6.8/10. Published 2021-12-30.
How severe is CVE-2021-20161?: Medium severity. CVSS v3 base score is 6.8 out of 10.