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Ac21 Firmware CVE-2026-1637

HIGH
Buffer Overflow (CWE-119)
2026-01-29 cna@vuldb.com
8.8
CVSS 3.1
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CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Analysis Generated
Mar 12, 2026 - 22:00 vuln.today
CVE Published
Jan 29, 2026 - 23:16 nvd
HIGH 8.8

DescriptionNVD

A vulnerability was identified in Tenda AC21 16.03.08.16. The affected element is the function fromAdvSetMacMtuWan of the file /goform/AdvSetMacMtuWan. The manipulation leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit is publicly available and might be used.

AnalysisAI

Tenda AC21 firmware versions up to 16.03.08.16 contain a stack-based buffer overflow in the /goform/AdvSetMacMtuWan endpoint that can be exploited remotely by authenticated attackers to achieve arbitrary code execution. Public exploit code exists for this vulnerability, and no patch is currently available. …

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RemediationAI

Within 24 hours: Inventory all Tenda AC21 devices in production and isolate affected units from critical network segments. Within 7 days: Implement network segmentation to restrict direct internet access to vulnerable devices and deploy WAF rules blocking requests to /goform/AdvSetMacMtuWan endpoint. …

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CVE-2026-1637 vulnerability details – vuln.today

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