CVE-2021-31755Tenda AC11 Router Stack Buffer Overflow Vulnerability

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.

9.8 CRITICALEPSS 86.51%⚡ Known Exploited (CISA KEV)NVD: Analyzed

Last updated: 2026-06-17 03:52 UTC

OverviewCVSS details

9.8CRITICALCVSS 3.1

Score source: NVD
NVD status: Analyzed
Published: May 7, 2021
Assigner: mitre

Affected

ac11 firmware (tenda)

Versions: through 02.03.01.104 cn

Exploitation

Public exploit: Yes · 1 reference
CISA KEV: Listed · Nov 3, 2021
KEV due date: Nov 17, 2021
Ransomware use: Unknown
SSVC: Exploitation active · Automatable yes · Impact total

EPSS · FIRST, scored Nov 7

86.51%chance of exploitation in 30 days

Higher than 99.74% of CVEs

CVSS 3.1 · NVD

9.8Critical

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

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

CVSS 2.0 · NVD

10.0High

AV:N/AC:L/Au:N/C:C/I:C/A:C

Attack vector: Network
Attack complexity: Low
Authentication: None
Confidentiality impact: Complete
Integrity impact: Complete
Availability impact: Complete

NVD status: Analyzed

Overview Affected Products References

NVD CVE.org

Overview

Severity

Score	Severity	Version	Vector String
9.8	CRITICAL	3.1NVD	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0	HIGH	2.0NVD	AV:N/AC:L/Au:N/C:C/I:C/A:C

CISA required action

⚡ Known exploited · remediation due Nov 17, 2021

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Details

CVE ID: CVE-2021-31755
Status: Analyzed
Assigner (CNA): mitre
Published: May 7, 2021
Last modified: 2026-06-17 03:52 UTC
Weaknesses: CWE-787

Sources

Refreshed hourly from the sources above. Last fetched 2026-11-08 10:40 UTC.