CVE-2025-3693 is a High severity (CVSS 8.8) stack based buffer overflow in the Tenda W12 firmware 3.0.0.5. The cgiWifiRadioSet function of the httpd web server is affected. The record names no fixed firmware, so limit management access and watch for a Tenda update.
What's affected
The record names the Tenda W12 running firmware 3.0.0.5. The vulnerable function is cgiWifiRadioSet in the file /bin/httpd, which is the router's web management server.
The record names no fixed firmware, and I found no Tenda advisory. The reporter's public issue is the only technical reference in the record. Check the Tenda support site for newer W12 firmware and read its release notes for the CVE or a fix to the wireless settings handler.
How to check if you're exposed
Log in to the router's management page and read the firmware version on the status or system page. If it shows 3.0.0.5, you are in scope. For several sites, record the firmware version for every Tenda device in your inventory.
Also check whether the management interface is reachable from the internet or from guest networks. The record says the attacker needs a low privilege login, so who holds an account matters as well.
What to do now
- Find every Tenda W12 and its firmware version.
- Check Tenda's support pages for a newer firmware and apply it when it addresses this flaw.
- Turn off remote management from the internet, and limit the management interface to a trusted wired host.
- Change default and shared admin passwords, since the flaw needs a login.
- If no fix appears, plan to replace the device with one that still receives security updates.
Why it matters
The weakness is CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-121 (Stack-based Buffer Overflow). The function that applies wireless radio settings copies a value from the request into a fixed size area on the stack without checking its length. Writing past that area can overwrite return addresses and let an attacker take control of the program. Routers often run the web server as the root user, so control of that process is control of the device.
The vector is network, low complexity, low privileges and no interaction, with high impact on confidentiality, integrity and availability, giving 8.8. The need for a login keeps it from Critical, but home and small office routers often keep default or weak passwords.
The record says the exploit has been disclosed to the public. It does not flag the CVE as exploited in the wild. A compromised router gives an attacker a view of every device behind it.
Quick check
Do I need a login to exploit it?
The vector in the record requires low privileges, so the attacker needs a valid login on the management interface.
Is there a fixed firmware?
The record names none. Check the Tenda support site and its release notes.
Sources
Last reviewed: 18 October 2026.
