CVE-2021-40546Public exploitNetwork attack vector

Authenticated router crash via oversized Wi-Fi password

Published Sep 5, 2023 · Updated Oct 1, 2024

Denial of service in Tenda AC6 firmware US_AC6V4.0RTL_V02.03.01.26_cn.bin allows remote authenticated users to crash the router. The /goform/setWifi handler accepts an oversized wifiPwd_5G value and crashes the device while processing the crafted Wi-Fi configuration request. An administrator password is required, and the reported crash leaves the router recoverable only by a physical reset.

CVSS severityUnavailable
Unscored
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Tenda AC6 firmware US_AC6V4.0RTL_V02.03.01.26_cn.bin allows remote authenticated users to crash the router. The /goform/setWifi handler accepts an oversized wifiPwd_5G value and crashes the device while processing the crafted Wi-Fi configuration request. An administrator password is required, and the reported crash leaves the router recoverable only by a physical reset.

The record

CVE
CVE-2021-40546
Published
Sep 5, 2023
Updated
Oct 1, 2024
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
AC6
Classifications
CWE-404, T1499
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Sep 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=us_ac6v4.0rtl_v02.03.01.26_cn.bin

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Shenzhen Tenda Technology Co., Ltd. · AC6version=us_ac6v4.0rtl_v02.03.01.26_cn.bin

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-404Improper Resource Shutdown or Release
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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