CVE-2026-71920
DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
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.
- Record
CVE-2026-71920- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
EUVDEUVD-2026-64979
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.
- Record
EUVD-2026-64979- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-648m-vmc5-h63x
Multiple DrayTek VigorSwitch models contain a null pointer dereference vulnerability in the...
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.
- Record
GHSA-648m-vmc5-h63x- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-71920- CVSS 4.0
- 6.9 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 4.9 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-476
- Updated
- 2026-11-02
Affected products
- draytek corporation vigorswitch fx2120
- draytek corporation vigorswitch g1280
- draytek corporation vigorswitch g1282
- draytek corporation vigorswitch g2100
- draytek corporation vigorswitch g2121
- draytek corporation vigorswitch g2280x
- draytek corporation vigorswitch g2282x
- draytek corporation vigorswitch g2540x
- draytek corporation vigorswitch g2540xs
- draytek corporation vigorswitch g2542x
- draytek corporation vigorswitch p1280
- draytek corporation vigorswitch p1281x
Show 16 moreShow less
- draytek corporation vigorswitch p1282
- draytek corporation vigorswitch p2100
- draytek corporation vigorswitch p2121
- draytek corporation vigorswitch p2280x
- draytek corporation vigorswitch p2282x
- draytek corporation vigorswitch p2540x
- draytek corporation vigorswitch p2540xs
- draytek corporation vigorswitch p2542x
- draytek corporation vigorswitch p2542xh
- draytek corporation vigorswitch pq2121x
- draytek corporation vigorswitch pq2200xb
- draytek corporation vigorswitch pq2300xb
- draytek corporation vigorswitch px2060
- draytek corporation vigorswitch q2121x
- draytek corporation vigorswitch q2200x
- draytek corporation vigorswitch q2300x
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-71920 is a medium vulnerability (CVSS 6.9) in Draytek Corporation Vigorswitch Fx2120, published August 24, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.56%, the 46th percentile. No source names a fixed version.