CVE-2021-31755

Name: CVE-2021-31755
Creator: NVD / NIST
Published: 2021-05-07T23:15:07.047+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 85.85%

Last modified Jun 17, 2026

CVE-2021-31755 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.. CISA has confirmed active exploitation in the wild. EPSS estimates a 85.85% chance of exploitation in the next 30 days.

Description

An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

85.85%

99.7th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Nov 17, 2021.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Tenda	Ac11 Firmware	<= 02.03.01.104_cn

References

https://github.com/Yu3H0/IoT_CVE/tree/main/Tenda/CVE_3Broken Link, Exploit, Issue Tracking, Third Party Advisory
https://github.com/Yu3H0/IoT_CVE/tree/main/Tenda/CVE_3Broken Link, Exploit, Issue Tracking, Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31755US Government Resource

Timeline

Published: May 7, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-31755?

How severe is CVE-2021-31755?

CVE-2021-31755 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 85.85% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-31755?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31755?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST