CVE-2025-8939 Tenda AC20 WifiGuestSet buffer overflow
Remote attackers can trigger a buffer overflow in the Tenda AC20 router's WifiGuestSet interface, potentially leading to code execution or service disruption.
- 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-2025-8939?
CVE-2025-8939 is a high-severity memory corruption vulnerability in Tenda AC20, published on 14 Aug 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
A vulnerability was determined in Tenda AC20 up to 16.03.08.12. Affected is an unknown function of the file /goform/WifiGuestSet. The manipulation of the argument shareSpeed leads to buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.
Which versions are affected by CVE-2025-8939?
It affects 1 product.
Products include Tenda Ac20 Firmware.
How do I fix CVE-2025-8939?
No fix has been published for CVE-2025-8939 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-8939 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-8939 exists.
Other vulnerabilities in Tenda AC20
- CVE-2025-15356 Tenda AC20 PowerSaveSet sscanf buffer overflow
- CVE-2025-14654 Tenda AC20 httpd setPptpUserList formSetPPTPUserList stack-based overflow
- CVE-2025-14655 Tenda AC20 httpd SetSysAutoRebbotCfg formSetRebootTimer stack-based overflow
- CVE-2025-14656 Tenda AC20 openSchedWifi httpd buffer overflow
- CVE-2025-13258 Tenda AC20 WifiExtraSet buffer overflow
Sources
Also known as GHSA-vrw9-gr4h-7x8p.