Actively exploited · Published May 7, 2021 · Assigned by mitre

CVE-2021-31755

Critical 9.8 Exploited

In plain English

A critical-severity out-of-bounds write in AC11 Router from Tenda. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). The chance it is exploited in the next 30 days is estimated at 86.5% (higher than 99.7% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Apply updates per vendor instructions.

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)86.5%top 0.3% of all CVEs

Exploited in the wildYesCISA KEV since Nov 3, 2021

Attack tooling1Nuclei

CISA guidance

Apply updates per vendor instructions.

Federal agencies must remediate by Nov 17, 2021.

Official 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.

Affected products (as reported)

Vendor	Product	Versions
n/a	n/a	n/a

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/Yu3H0/IoT_CVE/tree/main/Tenda/CVE_3 x_refsource_MISC
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31755 government-resource