CVE-2026-1638 Tenda AC21 mDMZSetCfg command injection
Remote attackers can execute arbitrary commands on Tenda AC21 routers via the mDMZSetCfg interface, requiring immediate attention from network administrators.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-1638?
CVE-2026-1638 is a medium-severity command injection vulnerability in Tenda AC21, published on 29 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A security flaw has been discovered in Tenda AC21 1.1.1.1/1.dmzip/16.03.08.16. The impacted element is the function mDMZSetCfg of the file /goform/mDMZSetCfg. The manipulation of the argument dmzIp results in command injection. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.
Which versions are affected by CVE-2026-1638?
It affects 1 product.
Products include Tenda Ac21 Firmware.
How do I fix CVE-2026-1638?
No fix has been published for CVE-2026-1638 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-1638 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-1638 exists.
Other vulnerabilities in Tenda AC21
- CVE-2025-9605 Tenda AC21/AC23 GetParentControlInfo stack-based overflow
- CVE-2023-24333 Command injection in n/a
- CVE-2026-4565 Tenda AC21 SetNetControlList formSetQosBand buffer overflow
- CVE-2026-1637 Tenda AC21 AdvSetMacMtuWan fromAdvSetMacMtuWan stack-based overflow
- CVE-2025-13445 Tenda AC21 SetIpMacBind stack-based overflow
Sources
Also known as GHSA-2wx5-jfx2-287m.