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Vulnerability · Published Aug 24, 2026 · Assigned by VulnCheck

CVE-2026-71920DrayTek VigorSwitch Multiple Models NULL Pointer Dereference via formlogout

Medium 4.9

In plain English

A medium-severity null pointer dereference in VigorSwitch FX2120 from DrayTek Corporation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities).

Severity (CVSS 3.1)4.9Medium
Exploit odds (30 days)0.6%top 53.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected products (as reported)

VendorProductVersions
DrayTek Corporation VigorSwitch G2540xs 0 – before 3.9.10
DrayTek Corporation VigorSwitch P2540xs 0 – before 3.9.10
DrayTek Corporation VigorSwitch FX2120 0 – before 3.9.10
DrayTek Corporation VigorSwitch G2282x 0 – before 2.10.6
DrayTek Corporation VigorSwitch P2282x 0 – before 2.10.6
DrayTek Corporation VigorSwitch Q2300x 0 – before 2.10.7
DrayTek Corporation VigorSwitch PQ2300xb 0 – before 2.10.7
DrayTek Corporation VigorSwitch G2542x 0 – before 3.10.6
DrayTek Corporation VigorSwitch P2542x 0 – before 3.10.6
DrayTek Corporation VigorSwitch P2542xh 0 – before 3.10.6
DrayTek Corporation VigorSwitch PX2060 0 – before 2.9.10
DrayTek Corporation VigorSwitch G1280 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1280 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1281x 0 – before 2.9.10
DrayTek Corporation VigorSwitch G1282 0 – before 2.9.10
DrayTek Corporation VigorSwitch P1282 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2121 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2121 0 – before 2.9.10
DrayTek Corporation VigorSwitch PQ2121x 0 – before 2.9.10
DrayTek Corporation VigorSwitch Q2121x 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2280x 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2280x 0 – before 2.9.10
DrayTek Corporation VigorSwitch Q2200x 0 – before 2.9.10
DrayTek Corporation VigorSwitch PQ2200xb 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2100 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2100 0 – before 2.9.10
DrayTek Corporation VigorSwitch G2540x 0 – before 2.9.10
DrayTek Corporation VigorSwitch P2540x 0 – before 2.9.10

Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

References