Executive brief
DrayTek VigorSwitch is a network switch used to manage and route traffic in corporate and service provider environments. A null pointer dereference vulnerability in the device's web management interface allows an authenticated attacker to crash the service, causing a temporary denial of service. An attacker must have valid administrative credentials to exploit this issue.
Technical details
The vulnerability is a null pointer dereference (CWE-476) in the formlogout function caused by missing validation of the Cookie header before string handling. An attacker must send a crafted HTTP request with an empty or absent Cookie header to trigger the crash. Exploitation requires valid administrative credentials to access the web management interface, limiting the attack surface to authenticated adversaries. A successful exploit causes the web service process to crash, resulting in denial of service until the service is restarted. Fixed versions have been released for all affected models.
Affected products
- DrayTek VigorSwitch G2540xs before 3.9.10
- DrayTek VigorSwitch P2540xs before 3.9.10
- DrayTek VigorSwitch FX2120 before 3.9.10
- DrayTek VigorSwitch G2282x before 2.10.6
- DrayTek VigorSwitch P2282x before 2.10.6
- DrayTek VigorSwitch Q2300x before 2.10.7
- DrayTek VigorSwitch PQ2300xb before 2.10.7
- DrayTek VigorSwitch G2542x before 3.10.6
- DrayTek VigorSwitch P2542x before 3.10.6
- DrayTek VigorSwitch P2542xh before 3.10.6
- DrayTek VigorSwitch PX2060 before 2.9.10
- DrayTek VigorSwitch G1280 before 2.9.10
- DrayTek VigorSwitch P1280 before 2.9.10
- DrayTek VigorSwitch P1281x before 2.9.10
- DrayTek VigorSwitch G1282 before 2.9.10
- DrayTek VigorSwitch P1282 before 2.9.10
- DrayTek VigorSwitch G2121 before 2.9.10
- DrayTek VigorSwitch P2121 before 2.9.10
- DrayTek VigorSwitch PQ2121x before 2.9.10
- DrayTek VigorSwitch Q2121x before 2.9.10
- DrayTek VigorSwitch G2280x before 2.9.10
- DrayTek VigorSwitch P2280x before 2.9.10
- DrayTek VigorSwitch Q2200x before 2.9.10
- DrayTek VigorSwitch PQ2200xb before 2.9.10
- DrayTek VigorSwitch G2100 before 2.9.10
- DrayTek VigorSwitch P2100 before 2.9.10
- DrayTek VigorSwitch G2540x before 2.9.10
- DrayTek VigorSwitch P2540x before 2.9.10
Timeline
- 2026-08-24: disclosed
- 2026-08-24: patched: Fixed firmware versions released for all affected models