Pierluigi Paganini November 27, 2025

ASUS released new firmware to address multiple vulnerabilities, including a critical authentication bypass flaw in routers with AiCloud enabled.

ASUS has issued new firmware addressing nine security vulnerabilities, including a critical authentication bypass, tracked as CVE-2025-59366 (CVSS score of 9.2), affecting routers with AiCloud enabled.

“Researchers have reported potential vulnerabilities in ASUS Router.  ASUS has released mitigations for these vulnerabilities.” reads the advisory published by the Taiwanese vendor. “To protect your devices, ASUS strongly recommends that all users update their router firmware to the
latest version immediately.”

AiCloud is a remote access feature built into many ASUS routers that allows devices to function as personal cloud servers for remote media streaming and cloud storage.

“An authentication-bypass vulnerability exists in AiCloud. This vulnerability can be triggered by an unintended side effect of the Samba functionality, potentially leading to allow execution of specific functions without proper authorization.” reads the advisory.

The company recommends that customers update the firmware (released on 2025-10) of their routers:

The vendor also provided mitigations for customers using end-of-life models, including the usage of strong, unique passwords for both your router login and WiFi. To reduce exposure and improve security, the company recommends disabling all internet-facing services, such as AiCloud, WAN remote access, port forwarding, DDNS, VPN server, DMZ, port triggering, and FTP.

End-of-life ASUS routers are prime targets of bots. Recently a new campaign called Operation WrtHug has compromised tens of thousands of outdated or end-of-life ASUS routers worldwide, mainly in Taiwan, the U.S., and Russia, pulling them into a large malicious network.

Threat actors exploited multiple ASUS router vulnerabilities, including OS command injection (CVE-2023-41345 to CVE-2023-41348), arbitrary command execution (CVE-2024-12912), and improper authentication (CVE-2025-2492), targeting the AiCloud service for initial access.

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Pierluigi Paganini

(SecurityAffairs – hacking, newsletter)