CVE-2025-29846 is a path traversal vulnerability identified in Synology Router Manager (SRM) version 1.3, specifically within the portenable CGI interface. This vulnerability arises from improper limitation of pathnames to restricted directories, allowing authenticated users with high privileges to access information beyond intended boundaries. The flaw enables these users to retrieve the status of installed packages, potentially exposing sensitive system information that could be leveraged for further attacks. The vulnerability is remotely exploitable over the network without requiring user interaction, but it does require the attacker to have authenticated access with high privileges, which limits the attack surface to insiders or compromised accounts. The CVSS v3.1 base score is 7.2, indicating a high severity due to the combined impact on confidentiality, integrity, and availability. Although no public exploits are currently known, the vulnerability's nature suggests that attackers could use it to gain deeper insight into system configurations and possibly manipulate package states, affecting system stability and security. The vulnerability was reserved in March 2025 and published in December 2025, with no patches currently linked, emphasizing the need for proactive mitigation. Synology SRM is widely used in small to medium enterprises and home networks, making this vulnerability relevant for a broad range of users. The path traversal issue reflects a common security weakness where input validation fails to restrict directory access, a critical concern in network device security.

For European organizations, this vulnerability poses significant risks, particularly for those relying on Synology SRM 1.3 routers for network management and security. The ability for an authenticated user to perform path traversal and access package status information can lead to exposure of sensitive configuration data, which may facilitate lateral movement or privilege escalation within the network. This can compromise the confidentiality of internal network configurations and the integrity of installed software packages, potentially allowing attackers to disrupt services or introduce malicious components. The availability of network services could also be impacted if attackers manipulate or disable critical packages. Given the widespread use of Synology devices in European SMEs and critical infrastructure sectors, the vulnerability could affect operational continuity and data protection compliance. The requirement for authenticated access somewhat limits the threat to insiders or attackers who have already compromised credentials, but the high impact on all security pillars (confidentiality, integrity, availability) warrants urgent attention. Additionally, the lack of known exploits currently provides a window for mitigation before active exploitation occurs.

Organizations should immediately restrict access to the portenable CGI interface on Synology SRM devices by implementing network segmentation and access control lists to limit exposure to trusted administrators only. Monitoring and logging of authenticated access to this interface should be enhanced to detect unusual or unauthorized activity promptly. Until an official patch is released, consider disabling or restricting the functionality of the portenable CGI endpoint if feasible. Employ strong authentication mechanisms, including multi-factor authentication, to reduce the risk of credential compromise. Regularly audit user privileges to ensure only necessary personnel have high-level access to the router management interface. Network administrators should also maintain up-to-date backups of router configurations and installed packages to enable rapid recovery in case of compromise. Finally, stay informed on Synology’s security advisories and apply patches immediately once available to remediate the vulnerability definitively.