CVE-2026-71923: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in DrayTek Corporation VigorSwitch G2540xs

This vulnerability affects multiple DrayTek VigorSwitch models, specifically the G2540xs. The root cause is improper neutralization of special elements in the username and password fields before executing OS commands in the auth_set function. An attacker who has valid administrative credentials to the device's web management interface can supply crafted input to trigger arbitrary command execution with root privileges. The CVSS 4.0 vector indicates network attack vector, low attack complexity, no user interaction, and high privileges required, with high impact on confidentiality, integrity, and availability.

Successful exploitation allows an attacker with administrative access to execute arbitrary OS commands with root privileges on the affected device. This can lead to full compromise of the device, potentially impacting network operations and security. However, exploitation requires valid administrative credentials, limiting the attack surface to authorized users or those who have obtained such credentials.

No official patch or remediation guidance is currently available from the vendor. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is released, restrict administrative access to trusted users only and monitor for suspicious activity involving administrative credentials.