CVE-2021-31755
Tenda AC11 Router Stack Buffer Overflow Vulnerability
- Critical 9.8
- Exploited: added to CISA KEV 3 Nov 2021
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.
Key facts
- Published
- 7 May 2021
- Last changed
- 21 Oct 2025
- Assigned by
- mitre
- KEV added
- 3 Nov 2021
- KEV fix due
- 17 Nov 2021
- EPSS
- 86.511% likely to be exploited in the next 30 days, higher than 99.743% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: yes; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 9.8CVSS 3.1, Criticalfrom CISA (ADP container)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
What to do
- Apply updates per vendor instructions.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| n/a | n/a |
|
Timeline
- 7 May 2021 Published
- 3 Nov 2021 CVE-2021-31755 added to CISA KEV
- 3 Nov 2021 Added to the CISA KEV catalogue