Buffer Overflow Vulnerability in DrayTek VigorSwitch Products
CVE-2026-71935

8.6HIGH

Key Information:

Vendor

Draytek Corporation

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

What is CVE-2026-71935?

Multiple models of DrayTek VigorSwitch have a vulnerability within the webBackupAction function, triggered by inadequate handling of input data. Specifically, the issue arises due to repeated concatenation of various input fields into fixed-size buffers without proper length validation. This oversight allows a remote attacker with valid administrative access to craft malicious inputs that can lead to a denial of service or potentially execute arbitrary commands on the device. Addressing this issue promptly is essential for maintaining the security of network infrastructures utilizing VigorSwitch devices.

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:
8.6
Severity:
HIGH
Confidentiality:
High
Integrity:
High
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)
.