Zyxel security advisory (AV25-686)

Serial number: AV25-686
Date: October 21, 2025

On October 21, 2025, Zyxel published a security advisory to address vulnerabilities in the following products:

• ATP – versions ZLD V4.32 to V5.40
• USG FLEX – versions ZLD V4.50 to V5.40
• USG FLEX 50(W)/ USG20(W)-VPN – versions ZLD V4.16 to V5.40

The Cyber Centre encourages users and administrators to review the provided web links and apply the necessary updates.

• Zyxel security advisory for post-authentication command injection and missing authorization vulnerabilities in ZLD firewalls
• Zyxel Advisories