CVE-2025-1732: Privilege Escalation in Zyxel USG FLEX H Series

Successful exploitation of CVE-2025-1732 could allow an attacker with administrator access to gain complete control over the affected Zyxel USG FLEX H series device. This could involve modifying firewall rules, accessing sensitive data stored on the device, or using the device as a pivot point to attack other systems on the network. The impact is particularly severe because it allows privilege escalation from an already-authenticated administrator account, bypassing standard access controls. The ability to upload a crafted configuration file provides a flexible attack vector, allowing for a wide range of malicious actions.

1. Reserved2025-02-27
2. Published2025-04-22
3. Modified2026-02-26
4. EPSS updated2026-03-23

The primary mitigation for CVE-2025-1732 is to upgrade the Zyxel USG FLEX H series uOS firmware to a patched version. Zyxel has released firmware updates to address this vulnerability; refer to their advisory for specific version details. As a temporary workaround, restrict access to the recovery function to trusted administrators only. Consider implementing stricter file validation on uploaded configuration files to prevent malicious content from being processed. Monitor system logs for suspicious activity related to configuration file uploads.