CVE-2024-5401: Synology DSM Privilege Escalation Vulnerability

CVE-2024-5401 Overview

CVE-2024-5401 is a high-severity vulnerability affecting the WebAPI component of Synology DiskStation Manager (DSM) and Synology Unified Controller (DSMUC). The flaw stems from improper control of dynamically-managed code resources [CWE-913]. Remote authenticated users can obtain elevated privileges through unspecified vectors without consent from legitimate administrators. Synology addressed the issue in DSM 7.1.1-42962-8, 7.2.1-69057-2, 7.2.2-72806, and DSMUC 3.1.4-23079. The vulnerability is network-exploitable and impacts confidentiality, integrity, and availability of affected network-attached storage (NAS) systems.

Critical Impact
Authenticated attackers on the network can escalate privileges on Synology NAS appliances, potentially gaining administrative control over stored data and system configurations.

Affected Products

Synology DiskStation Manager (DSM) versions prior to 7.1.1-42962-8
Synology DiskStation Manager (DSM) versions prior to 7.2.1-69057-2 and 7.2.2-72806
Synology Unified Controller (DSMUC) versions prior to 3.1.4-23079

Discovery Timeline

2025-12-04 - CVE-2024-5401 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-5401

Vulnerability Analysis

The vulnerability resides in the WebAPI component of Synology DSM, which exposes management functions over HTTP/HTTPS. Improper control of dynamically-managed code resources allows an attacker with valid credentials to influence how the application resolves and loads code at runtime. This class of weakness, tracked as [CWE-913], commonly arises when an application accepts identifiers or parameters that map to executable resources without adequate validation. Successful exploitation grants the attacker privileges beyond those originally assigned to their account.

Root Cause

The root cause is insufficient validation of dynamically-loaded code paths within the WebAPI handler logic. When the application resolves references to modules, functions, or configuration objects, it fails to enforce boundaries between low-privilege user contexts and privileged administrative code. Synology has not publicly disclosed the specific WebAPI endpoint or code path affected.

Attack Vector

Exploitation requires network access to the DSM WebAPI and valid user credentials. The attacker submits crafted requests to the vulnerable WebAPI endpoint, causing the application to invoke privileged code paths on their behalf. No user interaction from an administrator is required. Because DSM is often exposed to internal networks and, in some deployments, the internet, the attack surface extends across any account with WebAPI access. Synology has not documented specific proof-of-concept vectors in its advisory. Refer to the Synology Security Advisory SA-24-27 for vendor-supplied technical guidance.

Detection Methods for CVE-2024-5401

Indicators of Compromise

Unexpected creation of administrator accounts or modification of existing account roles within DSM.
WebAPI requests originating from low-privilege user sessions that trigger administrative actions in DSM audit logs.
Anomalous SSH, Telnet, or shell service enablement following WebAPI activity.

Detection Strategies

Enable DSM's built-in Log Center and forward logs to a centralized SIEM for correlation of privilege changes with WebAPI request patterns.
Baseline normal WebAPI usage per user account and alert on deviations, such as calls to administrative endpoints from standard users.
Review recent package installations, scheduled tasks, and shared folder permission changes for unauthorized modifications.

Monitoring Recommendations

Monitor DSM version strings across the fleet to identify appliances still running vulnerable builds.
Track authentication events and correlate failed logins followed by successful sessions and privilege escalations.
Alert on outbound network connections from DSM appliances to unfamiliar destinations, which may indicate post-exploitation activity.

How to Mitigate CVE-2024-5401

Immediate Actions Required

Upgrade DSM to 7.1.1-42962-8, 7.2.1-69057-2, 7.2.2-72806, or later, and DSMUC to 3.1.4-23079 or later.
Audit all DSM user accounts and remove or disable inactive or unnecessary accounts with WebAPI access.
Rotate credentials for administrative and service accounts on affected appliances after patching.

Patch Information

Synology released fixed builds referenced in the Synology Security Advisory SA-24-27. Administrators should apply the corresponding update for their DSM or DSMUC branch through Control Panel > Update & Restore, or download the DSM patch package directly from the Synology Download Center and install it manually.

Workarounds

Restrict DSM WebAPI exposure to trusted management networks using firewall rules or VPN-only access.
Enforce multi-factor authentication (MFA) for all DSM accounts to reduce the risk of credential-based exploitation.
Disable or limit accounts that do not require WebAPI or administrative access, and enable DSM's Auto Block and Account Protection features.

bash

# Example: restrict DSM WebAPI access via firewall rule (conceptual)
# Applied in Control Panel > Security > Firewall
# Allow only management subnet 10.10.20.0/24 to reach ports 5000/5001
source: 10.10.20.0/24  ports: 5000,5001  action: allow
source: any            ports: 5000,5001  action: deny