CVE-2026-5204Public exploitNetwork attack vector

Authenticated code execution via unchecked strcat

Published Mar 31, 2026 · Updated Mar 31, 2026

Stack-based buffer overflow in Tenda CH22 firmware 1.0.0.1 allows remote authenticated users to execute code via a crafted webSiteId. The formWebTypeLibrary function passes webSiteId to strcat without a length check, overflowing its stack buffer at /goform/webtypelibrary. Low-privilege access to the router's web interface is required; a crafted POST can crash httpd or execute code with that process's privileges.

CVSS severity8.8
High
EPSS probability2.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Stack-based buffer overflow in Tenda CH22 firmware 1.0.0.1 allows remote authenticated users to execute code via a crafted webSiteId. The formWebTypeLibrary function passes webSiteId to strcat without a length check, overflowing its stack buffer at /goform/webtypelibrary. Low-privilege access to the router's web interface is required; a crafted POST can crash httpd or execute code with that process's privileges.

The record

CVE
CVE-2026-5204
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
Shenzhen Tenda Technology Co., Ltd.
Product
CH22 Firmware
Classifications
CWE-121, CWE-787, CWE-119, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record 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=1.0.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Shenzhen Tenda Technology Co., Ltd. · CH22 Firmwareversion=1.0.0.1

Published CVSS scores

8.8VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.4VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
9.0VulDBAV:N/AC:L/Au:S/C:C/I:C/A:C

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-787Out-of-bounds Write
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1190Exploit Public-Facing Application

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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