CVE-2025-29846 is a path traversal vulnerability identified in Synology Router Manager (SRM) version 1.3, specifically within the portenable CGI interface. This flaw allows remote authenticated users to bypass intended directory restrictions and access information about installed packages on the device. The vulnerability arises from improper limitation of pathname inputs, enabling attackers to traverse directories outside the restricted scope. Although exploitation requires valid authentication credentials, no user interaction is necessary, and the attack can be conducted remotely over the network. The vulnerability impacts confidentiality by exposing potentially sensitive package status information, integrity by enabling unauthorized access to system components, and availability if leveraged as part of a broader attack. The CVSS 3.1 base score of 7.2 reflects a high severity with network attack vector, low attack complexity, and high impact on confidentiality, integrity, and availability. No public exploits have been reported yet, but the vulnerability's nature makes it a significant risk for environments using Synology SRM devices. The lack of available patches at the time of disclosure necessitates immediate risk mitigation through access controls and monitoring. Given Synology's popularity in small to medium enterprise and home office environments, the vulnerability could be leveraged for reconnaissance or as a stepping stone for further compromise.

For European organizations, this vulnerability poses a substantial risk due to the widespread use of Synology SRM devices in enterprise and critical infrastructure networks. Exposure of installed package status can provide attackers with valuable intelligence to tailor subsequent attacks, potentially leading to privilege escalation or lateral movement within networks. Confidentiality breaches could result in leakage of sensitive operational details, while integrity and availability impacts could disrupt network management and services. Organizations relying on these routers for secure network perimeter defense may face increased risk of compromise. The requirement for authentication reduces the attack surface but does not eliminate risk, especially if credential management is weak or compromised. The vulnerability could be exploited in targeted attacks against sectors such as finance, healthcare, and government, where Synology devices are deployed. Additionally, the absence of known exploits currently provides a window for proactive defense, but also underscores the urgency for patching once available.

Organizations should immediately audit and restrict access to Synology SRM management interfaces, ensuring they are not exposed to untrusted networks or the internet. Implement strong authentication mechanisms, including multi-factor authentication, to reduce the risk of credential compromise. Monitor logs and network traffic for unusual access patterns to the portenable CGI interface or attempts to access restricted directories. Maintain an inventory of all Synology SRM devices and verify their firmware versions, prioritizing upgrades once Synology releases patches addressing CVE-2025-29846. Employ network segmentation to isolate management interfaces from general user networks. Consider deploying web application firewalls or intrusion detection/prevention systems with rules tailored to detect path traversal attempts. Educate administrators about the vulnerability and the importance of credential hygiene. Finally, establish incident response plans to quickly address any suspected exploitation attempts.