CVE-2020-36946 SyncBreeze 10.0.28 - 'login' Denial of Service

High 8.7 Published 27 Jan 2026 Updated 7 Apr 2026

Remote attackers can crash the SyncBreeze service by sending oversized payloads to the login endpoint, disrupting availability.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2020-36946?

CVE-2020-36946 is a high-severity denial of service vulnerability in Flexense Ltd. SyncBreeze, published on 27 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-770

Which versions are affected by CVE-2020-36946?

It affects 1 product.

Products include Flexense Syncbreeze.

How do I fix CVE-2020-36946?

No fix has been published for CVE-2020-36946 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-36946 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36946 exists.

Sources

Also known as GHSA-xmhr-f2x4-rvcv.