CVE-2025-59367 in DSL-AC51
Summary
by MITRE • 11/13/2025
An authentication bypass vulnerability has been identified in certain DSL series routers, may allow remote attackers to gain unauthorized access into the affected system. Refer to the 'Security Update for DSL Series Router' section on the ASUS Security Advisory for more information.
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Analysis
by VulDB Data Team • 02/06/2026
The vulnerability identified as CVE-2025-59367 represents a critical authentication bypass flaw affecting specific models within the DSL series of routers manufactured by ASUS. This security weakness resides in the router's authentication mechanisms, potentially allowing remote attackers to circumvent the standard login procedures without proper credentials. The vulnerability's classification as an authentication bypass aligns with CWE-287, which addresses improper authentication issues in software systems. Such flaws typically arise from insufficient validation of user credentials or flawed session management protocols that enable unauthorized access to network devices.
The technical implementation of this vulnerability likely involves a weakness in the router's web-based management interface or API endpoints that handle authentication requests. Attackers exploiting this flaw could potentially access administrative functions, modify router configurations, or establish persistent access to the network infrastructure. The remote nature of the exploit means that attackers do not require physical access to the device or local network presence to leverage this vulnerability. This characteristic significantly increases the attack surface and potential impact, as the vulnerability can be exploited from anywhere on the internet without requiring specialized network access or insider knowledge.
From an operational impact perspective, this vulnerability creates substantial risk for organizations and individuals relying on affected ASUS DSL series routers for network connectivity. Successful exploitation could lead to complete network compromise, enabling attackers to monitor traffic, redirect connections, modify firewall rules, or establish backdoors for continued access. The vulnerability may also facilitate lateral movement within networks, as compromised routers often serve as gateway points for internal systems. According to ATT&CK framework, this vulnerability maps to T1078 (Valid Accounts) and T1566 (Phishing), as it allows attackers to gain unauthorized access using legitimate administrative credentials or by creating new accounts through the bypassed authentication mechanism.
Organizations should immediately implement mitigation strategies including applying the vendor-provided security update referenced in the ASUS Security Advisory. Network segmentation and monitoring of router management interfaces should be enhanced to detect unauthorized access attempts. Additionally, implementing multi-factor authentication mechanisms where available and regularly reviewing access logs can help identify potential exploitation attempts. The vulnerability underscores the importance of maintaining current firmware versions and following security best practices for network device management. Security teams should also consider conducting vulnerability assessments to identify other potentially affected devices within their network infrastructure and ensure proper network access controls are implemented to limit the impact of such vulnerabilities.