CVE-2022-40855Public exploitNetwork attack vector

Remote code execution via unchecked sprintf copy

Published Sep 23, 2022 · Updated May 22, 2025

Stack overflow in Tenda W20E firmware 15.11.0.6 allows remote attackers to execute code or crash the router via a crafted HTTP request. The formSetPortMapping handler passes five port-mapping parameters to sprintf, which concatenates them into the 256-byte sMibValue stack buffer without a size check. The management HTTP endpoint must be network-reachable; exploitation can overwrite the stack and either interrupt routing service or execute code on the appliance.

CVSS severity9.8
Critical
EPSS probability13.49%
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 Tenda W20E firmware 15.11.0.6 allows remote attackers to execute code or crash the router via a crafted HTTP request. The formSetPortMapping handler passes five port-mapping parameters to sprintf, which concatenates them into the 256-byte sMibValue stack buffer without a size check. The management HTTP endpoint must be network-reachable; exploitation can overwrite the stack and either interrupt routing service or execute code on the appliance.

The record

CVE
CVE-2022-40855
Published
Sep 23, 2022
Updated
May 22, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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