Incorrect Default Permissions in Synology Assistant

Synology has disclosed a vulnerability (CVE-2026-4793) affecting all versions of Synology Assistant prior to 7.0.7-50095. The flaw is categorized as an incorrect default permissions issue (CWE-276). During the installation or update process of the software, local users with low privileges can leverage insecure file permissions to read or write arbitrary files on the host filesystem. Furthermore, this vulnerability can be exploited to induce a denial-of-service condition. This issue is particularly relevant to environments where multiple local users share the same workstation, as it provides a pathway for a less-privileged user to impact system integrity or disrupt the installation of authorized security software. Defenders should prioritize updating Synology Assistant to version 7.0.7-50095 or later across all managed endpoints.

Impact

Successful exploitation allows a local, low-privileged user to bypass standard access controls to modify or exfiltrate sensitive files. The potential for denial-of-service also poses a risk to system stability during the installation phase. This vulnerability affects any environment where Synology Assistant is deployed, including workstations managed by enterprise IT.

Recommendation

• Update Synology Assistant to version 7.0.7-50095 or higher on all workstations immediately to remediate CVE-2026-4793.
• Audit endpoint software inventories to identify outdated versions of Synology Assistant that remain installed on sensitive workstations.
• Restrict local installation rights for standard users on high-security workstations to prevent the unauthorized execution of installers that may trigger this vulnerability.