CVE-2022-40866Public exploitNetwork attack vector

Code execution via unbounded debug-parameter formatting

Published Sep 23, 2022 · Updated May 22, 2025

Stack overflow in formSetDebugCfg in Tenda W20E 15.11.0.6 allows remote attackers to crash the router or execute code via HTTP. The handler passes unbounded enable, level, and module values to sprintf, which formats them into a 128-byte stack buffer. The published proof of concept reaches the management endpoint after an administrator login; unauthenticated reachability is not demonstrated there.

CVSS severity9.8
Critical
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack overflow in formSetDebugCfg in Tenda W20E 15.11.0.6 allows remote attackers to crash the router or execute code via HTTP. The handler passes unbounded enable, level, and module values to sprintf, which formats them into a 128-byte stack buffer. The published proof of concept reaches the management endpoint after an administrator login; unauthenticated reachability is not demonstrated there.

The record

CVE
CVE-2022-40866
Published
Sep 23, 2022
Updated
May 22, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1499.004, T1210
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 23, 2022CVE publishedPublication date reported by the CVE source.
  2. May 22, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation
T1210Exploitation of Remote Services

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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