CVE-2026-71920 DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
Remote authenticated attackers can crash DrayTek VigorSwitch devices via a null pointer dereference in the logout function.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-71920?
CVE-2026-71920 is a medium-severity vulnerability in DrayTek Corporation VigorSwitch FX2120, published on 24 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Multiple DrayTek VigorSwitch models contain a null pointer dereference vulnerability in the formlogout function. The vulnerability is caused by missing checks for an empty or absent Cookie header before string handling. A remote attacker can trigger this vulnerability via a crafted request to crash the service and cause a denial of service. Exploitation requires valid administrative credentials for the device's web management interface.
Weakness: CWE-476
Which versions are affected by CVE-2026-71920?
How do I fix CVE-2026-71920?
No fix has been published for CVE-2026-71920 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-71920 being exploited?
There is no known exploitation of CVE-2026-71920 in the wild and no public exploit code.
Sources
Also known as GHSA-648m-vmc5-h63x.