CVE-2020-36946 in SyncBreeze
Summary
by MITRE • 01/27/2026
SyncBreeze 10.0.28 contains a denial of service vulnerability in the login endpoint that allows remote attackers to crash the service. Attackers can send an oversized payload in the login request to overwhelm the application and potentially disrupt service availability.
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Analysis
by VulDB Data Team • 03/24/2026
The vulnerability identified as CVE-2020-36946 affects SyncBreeze version 10.0.28 and represents a critical denial of service flaw within the application's authentication mechanism. This issue resides in the login endpoint where the system fails to properly validate input length constraints, creating an avenue for malicious actors to exploit the service's resource handling capabilities. The vulnerability stems from inadequate payload size validation that allows attackers to submit login requests containing excessively large data inputs, leading to system instability and potential complete service disruption.
From a technical perspective this vulnerability manifests as a buffer overflow condition or memory exhaustion scenario within the login processing module. The flaw operates by exploiting the application's failure to implement proper input sanitization and length checking mechanisms before processing authentication requests. When an oversized payload is received, the system attempts to allocate memory or process the data without adequate bounds checking, resulting in resource exhaustion that causes the service to crash or become unresponsive. This type of vulnerability aligns with CWE-129, which describes improper validation of length of input buffers, and represents a classic example of insufficient input validation that can lead to resource exhaustion attacks.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides attackers with a straightforward method to compromise system availability and potentially impact business continuity operations. Remote attackers can exploit this weakness without requiring authentication credentials, making the attack surface particularly concerning for enterprise environments where SyncBreeze may be deployed for file synchronization and management tasks. The vulnerability affects the core authentication functionality, meaning that legitimate users would be unable to access the service during an active attack, while the system remains vulnerable to repeated exploitation attempts that could maintain persistent service disruption.
Security professionals should consider this vulnerability in the context of broader attack frameworks such as those outlined in the MITRE ATT&CK matrix where it would fall under the service stoppage category within the impact tactics. The vulnerability's remote exploitability and lack of authentication requirements make it particularly attractive to threat actors seeking to disrupt operations or mask other malicious activities. Organizations should prioritize immediate remediation through vendor-provided patches or updates, while implementing network-level controls such as rate limiting and payload size restrictions to mitigate potential exploitation attempts. Additionally, monitoring for unusual login request patterns and implementing proper input validation at multiple layers of the application architecture can help detect and prevent exploitation attempts before they can cause significant damage to service availability.