Pre-Authentication Null Pointer Dereference in DrayTek VigorSwitch Models
CVE-2026-71922

8.7HIGH

Key Information:

Vendor

Draytek Corporation

Status
Vigorswitch G2540xs
Vigorswitch P2540xs
Vigorswitch Fx2120
Vigorswitch G2282x
Vendor
CVE Published:
24 August 2026

What is CVE-2026-71922?

Multiple models of DrayTek VigorSwitch are susceptible to a pre-authentication null pointer dereference vulnerability. This issue arises from insufficient validation when the 'pass' field is not provided in requests sent to the setget.cgi interface. A remote attacker could exploit this vulnerability by crafting a specific request, potentially leading to service crashes and resulting in a denial of service for legitimate users. It is crucial for organizations using affected VigorSwitch models to implement appropriate security measures to mitigate this risk.

Affected Version(s)

VigorSwitch FX2120 0 < 3.9.10

VigorSwitch G1280 0 < 2.9.10

VigorSwitch G1282 0 < 2.9.10

References

https://www.draytek.com/about/security-advisory/multiple-...
vendor-advisory
https://www.vulncheck.com/advisories/draytek-vigorswitch-...
third-party-advisory

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jincheng Wang (@winmt)
Le Yu (Nanjing University of Posts and Telecommunications)
Xiapu Luo (The Hong Kong Polytechnic University)
.