CVE-2024-45539: Synology DiskStation Manager DOS Vulnerability

CVE-2024-45539 Overview

CVE-2024-45539 is an out-of-bounds write vulnerability [CWE-787] in Common Gateway Interface (CGI) components of Synology DiskStation Manager (DSM) and Synology Unified Controller (DSMUC). Remote attackers can trigger the flaw over the network without authentication or user interaction. Successful exploitation leads to denial-of-service conditions on affected storage appliances.

The vulnerability affects DSM versions prior to 7.2.1-69057-2 and 7.2.2-72806, as well as DSMUC versions prior to 3.1.4-23079. Synology published advisory SA-24-27 to address the issue.

Critical Impact
Unauthenticated remote attackers can crash CGI handlers in DSM and DSMUC, disrupting access to network-attached storage services without requiring credentials or user interaction.

Affected Products

Synology DiskStation Manager (DSM) versions before 7.2.1-69057-2
Synology DiskStation Manager (DSM) versions before 7.2.2-72806
Synology Unified Controller (DSMUC) versions before 3.1.4-23079

Discovery Timeline

2025-12-04 - CVE-2024-45539 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-45539

Vulnerability Analysis

The vulnerability resides in CGI components that handle requests served by DSM and DSMUC web interfaces. A remote attacker can send crafted network traffic that causes the CGI handler to write data outside the bounds of an allocated buffer. The resulting memory corruption destabilizes the affected process and produces a denial-of-service condition.

The flaw is reachable across the network and does not require prior authentication or user interaction. Because Synology appliances commonly host critical file shares, backup targets, and business workflows, an availability loss directly affects dependent services. Confidentiality and integrity are not impacted by this specific issue, according to the advisory metrics.

Root Cause

The root cause is an out-of-bounds write [CWE-787] in CGI request handling. The affected code paths fail to enforce sufficient boundary checks before writing attacker-controlled data into a fixed-size buffer. When the input exceeds expected limits, adjacent memory is overwritten, corrupting process state and forcing termination or restart of the service.

Attack Vector

The attack vector is network-based. An attacker sends a malicious HTTP request to a CGI endpoint exposed by DSM or DSMUC. Devices reachable from the internet, or from untrusted internal segments, face the highest exposure. Synology did not disclose the specific CGI component or request structure, and no public proof-of-concept is available at this time.

The vulnerability mechanism is described in vendor materials only. See the Synology Security Advisory SA-24-27 for vendor-provided technical context.

Detection Methods for CVE-2024-45539

Indicators of Compromise

Unexpected restarts or crashes of CGI handler processes on DSM or DSMUC appliances
DSM web management interface becoming intermittently unresponsive following inbound HTTP traffic
Repeated malformed or oversized HTTP requests targeting CGI endpoints in web server logs
Spikes in inbound connections to DSM management ports from unfamiliar source addresses

Detection Strategies

Inspect DSM web server logs for anomalous request bodies, oversized parameters, or unusual CGI query strings
Correlate appliance process crash events with inbound network traffic to identify exploitation attempts
Deploy network intrusion detection signatures that flag malformed HTTP requests directed at Synology management interfaces
Track DSM and DSMUC firmware versions across the fleet to identify unpatched assets exposed to the flaw

Monitoring Recommendations

Enable centralized syslog forwarding from DSM and DSMUC devices to a security analytics platform
Alert on repeated service restarts of CGI components and web management daemons
Monitor edge firewalls for unauthenticated external requests reaching DSM management ports
Establish baseline availability metrics for storage services and alert on deviations indicating denial-of-service activity

How to Mitigate CVE-2024-45539

Immediate Actions Required

Upgrade DSM to version 7.2.1-69057-2, 7.2.2-72806, or later as specified in Synology advisory SA-24-27
Upgrade DSMUC to version 3.1.4-23079 or later
Restrict network exposure of DSM and DSMUC management interfaces to trusted administrative networks only
Inventory all Synology appliances and verify firmware versions against the fixed releases

Patch Information

Synology released fixed firmware versions addressing this vulnerability. Administrators must upgrade DSM to 7.2.1-69057-2 or 7.2.2-72806, and DSMUC to 3.1.4-23079. Full remediation guidance is published in the Synology Security Advisory SA-24-27.

Workarounds

Block external access to DSM and DSMUC web management ports at the perimeter firewall until patches are applied
Place affected appliances behind a VPN or zero-trust access broker to require authenticated network access
Disable unused CGI-driven services and features on the appliance to reduce attack surface
Apply rate limiting on management interfaces to slow automated exploitation attempts

bash

# Example firewall rule restricting DSM management access to a trusted subnet
iptables -A INPUT -p tcp --dport 5000 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 5001 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 5000 -j DROP
iptables -A INPUT -p tcp --dport 5001 -j DROP