CVE-2026-71920

DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout

Published Aug 24, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout
First Time appeared Draytek
Draytek vigorswitch Fx2120 Firmware
Draytek vigorswitch G1282 Firmware
Draytek vigorswitch G2100 Firmware
Draytek vigorswitch G2121 Firmware
Draytek vigorswitch G2280x Firmware
Draytek vigorswitch G2540xs Firmware
Draytek vigorswitch P1282 Firmware
Draytek vigorswitch P2100 Firmware
Draytek vigorswitch P2280x Firmware
Draytek vigorswitch P2540xs Firmware
Draytek vigorswitch Pq2121x Firmware
Draytek vigorswitch Pq2200xb Firmware
Draytek vigorswitch Q2121x Firmware
Draytek vigorswitch Q2200x Firmware
Weaknesses CWE-476
CPEs cpe:2.3:o:draytek:vigorswitch_fx2120_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_g1282_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_g2100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_g2121_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_g2280x_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_g2540xs_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_p1282_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_p2100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_p2280x_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_p2540xs_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_pq2121x_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_pq2200xb_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_q2121x_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:draytek:vigorswitch_q2200x_firmware:*:*:*:*:*:*:*:*
Vendors & Products Draytek
Draytek vigorswitch Fx2120 Firmware
Draytek vigorswitch G1282 Firmware
Draytek vigorswitch G2100 Firmware
Draytek vigorswitch G2121 Firmware
Draytek vigorswitch G2280x Firmware
Draytek vigorswitch G2540xs Firmware
Draytek vigorswitch P1282 Firmware
Draytek vigorswitch P2100 Firmware
Draytek vigorswitch P2280x Firmware
Draytek vigorswitch P2540xs Firmware
Draytek vigorswitch Pq2121x Firmware
Draytek vigorswitch Pq2200xb Firmware
Draytek vigorswitch Q2121x Firmware
Draytek vigorswitch Q2200x Firmware
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6.9, 'vector': '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'}