CVE-2026-71936 HIGH

CVE-2026-71936: DrayTek VigorSwitch Multiple Models Buffer Overflow via sysreboot

Vendor Draytek Corporation
Product VigorSwitch G2540xs
Weakness CWE-120
Published August 24, 2026
Last update August 27, 2026

CVSS base score

8.6/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

What the vulnerability does

01Description

Multiple DrayTek VigorSwitch models contain a buffer overflow vulnerability in the sysreboot function. The vulnerability is caused by unsafe concatenation of split valueN data into a fixed-size buffer. A remote attacker can trigger this vulnerability via crafted input, causing a denial of service or potentially executing arbitrary commands. Exploitation requires valid administrative credentials for the device's web management interface.

Key dates

02Disclosure timeline

August 24, 2026 CVE published
August 27, 2026 Record updated