CVE-2020-36946
Published: 27 January 2026
Summary
CVE-2020-36946 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Flexense Syncbreeze. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 45.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability).
Deeper analysis
CVE-2020-36946 is a denial of service vulnerability in SyncBreeze version 10.0.28, specifically affecting the login endpoint. Remote attackers can exploit it by sending an oversized payload in the login request, which overwhelms the application and causes the service to crash, disrupting availability. The issue is classified under CWE-770 (Allocation of Resources Without Limits or Throttling) and carries a CVSS v3.1 base score of 7.5 (High).
The vulnerability is exploitable over the network (AV:N) with low attack complexity (AC:L), requiring no privileges (PR:N), no user interaction (UI:N), and no scope change (S:U), resulting in high impact to availability (A:H) with no impact to confidentiality or integrity (C:N/I:N). Any remote attacker can trigger the crash without authentication, potentially denying service to legitimate users relying on the SyncBreeze service.
Advisories and related resources, including those from VulnCheck at https://www.vulncheck.com/advisories/syncbreeze-login-denial-of-service and the vendor site at http://www.syncbreeze.com, provide further details on the issue. Proof-of-concept exploits are available on Exploit-DB at https://www.exploit-db.com/exploits/49291.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-30861
Vulnerability details
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
DoS via oversized login payload directly matches application exploitation for endpoint denial of service.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly implements denial-of-service protections like rate limiting and request size limits to block oversized payloads targeting the login endpoint.
Requires validation of information inputs such as login requests to reject oversized payloads that overwhelm and crash the application.
Protects resource availability by enforcing quotas and limits on allocations to mitigate exhaustion from malicious oversized login requests.