CVE-2020-37133 UltraVNC Launcher 1.2.4.0 - 'RepeaterHost' Denial of Service
Attackers can crash UltraVNC Launcher by pasting an overly long string into the Repeater Host configuration field.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2020-37133?
CVE-2020-37133 is a medium-severity denial of service vulnerability in UltraVNC Launcher, published on 5 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allows attackers to crash the application. Attackers can paste an overly long string of 300 characters into the Repeater Host property to trigger an application crash.
Which versions are affected by CVE-2020-37133?
It affects 1 product.
Products include Uvnc Ultravnc.
How do I fix CVE-2020-37133?
No fix has been published for CVE-2020-37133 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-2020-37133 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-37133 exists.
Other vulnerabilities in UltraVNC Launcher
Sources
Also known as GHSA-xxc7-rq23-x492.