CVE-2026-71920: DrayTek Corporation Vigorswitch FX2120

Medium severity, CVSS 4.9. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• DrayTek Corporation Vigorswitch FX2120: before 3.9.10 (fixed in 3.9.10)
• DrayTek Corporation Vigorswitch g1280: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g1282: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g2100: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g2121: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g2280x: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g2282x: before 2.10.6 (fixed in 2.10.6)
• DrayTek Corporation Vigorswitch g2540x: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch g2540xs: before 3.9.10 (fixed in 3.9.10)
• DrayTek Corporation Vigorswitch g2542x: before 3.10.6 (fixed in 3.10.6)
• DrayTek Corporation Vigorswitch p1280: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p1281x: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p1282: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p2100: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p2121: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p2280x: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p2282x: before 2.10.6 (fixed in 2.10.6)
• DrayTek Corporation Vigorswitch p2540x: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch p2540xs: before 3.9.10 (fixed in 3.9.10)
• DrayTek Corporation Vigorswitch p2542x: before 3.10.6 (fixed in 3.10.6)
• DrayTek Corporation Vigorswitch p2542xh: before 3.10.6 (fixed in 3.10.6)
• DrayTek Corporation Vigorswitch PQ2121X: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch PQ2200XB: before 2.9.10 (fixed in 2.9.10)
• DrayTek Corporation Vigorswitch PQ2300XB: before 2.10.7 (fixed in 2.10.7)
• DrayTek Corporation Vigorswitch PX2060: before 2.9.10 (fixed in 2.9.10)
• and 3 more

Published 2026-08-24. Last modified 2026-08-26.