CVE-2026-34008 in Notes Station
Summary
by MITRE • 10/15/2026
An incorrect permission assignment for critical resource vulnerability has been reported to affect Notes Station 3. If a local attacker gains a user account, they can then exploit the vulnerability to compromise the security of the system.
We have already fixed the vulnerability in the following version: Notes Station 3 3.9.11 and later
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Analysis
by VulDB Data Team • 10/15/2026
The reported vulnerability in Synology Notes Station 3 represents a classic instance of improper access control, specifically categorized under CWE-284 as Improper Access Control. This flaw arises from an incorrect assignment of permissions to critical system resources within the application's architecture. In secure software design, every resource such as files, database entries, or API endpoints must be protected by robust authentication and authorization mechanisms that strictly enforce least privilege principles. When these controls are misconfigured or implemented incorrectly, it creates a pathway for unauthorized entities to interact with sensitive data or functionality intended only for privileged users or the system itself. The severity of this issue is compounded by its reliance on local attacker access; while remote exploitation is not indicated, any user who manages to obtain a valid account on the target NAS device can leverage this weakness to escalate their privileges or exfiltrate confidential information stored within the Notes Station environment.
From an operational perspective, the impact of this vulnerability extends beyond simple data leakage. If a local attacker successfully exploits this permission flaw, they may be able to read, modify, or delete notes belonging to other users, including potentially administrative accounts if the misconfiguration is severe enough. This directly compromises the confidentiality and integrity aspects of the CIA triad. Furthermore, depending on how Notes Station integrates with broader Synology DSM features, an attacker might use this foothold as a stepping stone for further lateral movement within the network or attempt to manipulate system configurations that rely on user-specific data structures. The ability to compromise security through a standard user account underscores a failure in boundary enforcement between different privilege levels, allowing low-privileged users to perform actions reserved for higher-privileged roles or administrators.
In terms of threat modeling and industry frameworks, this vulnerability aligns with the MITRE ATT&CK technique T1078, Valid Accounts, where attackers use legitimate credentials to gain access. The exploitation path typically involves initial compromise via phishing, credential stuffing, or other means that result in a low-privileged user account, followed by privilege escalation through the identified permission flaw. This scenario highlights the critical importance of defense-in-depth strategies; relying solely on perimeter defenses is insufficient when internal trust boundaries are weak. Organizations must ensure that applications like Notes Station adhere to strict security coding standards and undergo rigorous penetration testing focused specifically on access control logic before deployment in production environments.
To mitigate this risk, immediate action is required by upgrading the Synology NAS operating system and its application packages to version 3.9.11 or later of Notes Station, as indicated by the vendor's remediation guidance. This update contains the necessary code changes to correct the permission assignments for critical resources, thereby restoring proper access control mechanisms. In addition to applying this patch, administrators should review their overall user management policies. It is advisable to enforce strong password complexity requirements and multi-factor authentication where possible to reduce the likelihood of initial account compromise. Regular audits of user permissions within DSM and specific applications can help identify any lingering misconfigurations that might expose similar vulnerabilities in other services running on the same infrastructure.