Command Injection Vulnerability in Tenda AC21 Router
CVE-2026-1638

5.3MEDIUM

Key Information:

Vendor

Tenda
Status
Ac21
Vendor
CVE Published:
29 January 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-1638?

A significant security vulnerability has been identified in the Tenda AC21 router, specifically within the mDMZSetCfg function located in the /goform/mDMZSetCfg file. This vulnerability allows an attacker to manipulate the dmzIp argument, leading to potential command injection that can be executed remotely. The exploit has been made public, posing a serious risk to affected users and network security. It is crucial for users of the Tenda AC21 to assess their exposure and apply necessary updates to mitigate such risks.

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Affected Version(s)

AC21 1.1.1.1

AC21 1.dmzip

AC21 16.03.08.16

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-1638 - Proof of Concept

References

https://vuldb.com/?id.343417
vdb-entrytechnical-description
https://vuldb.com/?ctiid.343417
signaturepermissions-required
https://vuldb.com/?submit.740871
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

LX-LX (VulDB User)
JSON
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