Stack-Based Buffer Overflow Vulnerability in Tenda AC21 Router
CVE-2026-1637

8.7HIGH

Key Information:

Vendor

Tenda
Status
Ac21
Vendor
CVE Published:
29 January 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-1637?

A stack-based buffer overflow vulnerability affects the Tenda AC21 router, specifically within the fromAdvSetMacMtuWan function located in the /goform/AdvSetMacMtuWan file. This flaw enables an attacker to potentially execute arbitrary code remotely. Given that exploits for this vulnerability are publicly available, it poses a significant security concern for users of the Tenda AC21 router version 16.03.08.16.

Affected Version(s)

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-2026-1637 - Proof of Concept

References

https://vuldb.com/?id.343416
vdb-entrytechnical-description
https://vuldb.com/?ctiid.343416
signaturepermissions-required
https://vuldb.com/?submit.740865
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
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)
.