CVE-2020-36872 BACnet Test Server 1.01 Malformed BVLC Length DoS
Remote attackers can crash the BACnet Test Server by sending malformed BVLC length values, causing a denial of service.
- 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-2020-36872?
CVE-2020-36872 is a high-severity denial of service vulnerability in BACnet Test Server, published on 26 Nov 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
BACnet Test Server versions up to and including 1.01 contains a remote denial of service vulnerability in its BACnet/IP BVLC packet handling. The server fails to properly validate the BVLC Length field in incoming UDP BVLC frames on the default BACnet port (47808/udp). A remote unauthenticated attacker can send a malformed BVLC Length value to trigger an access violation and crash the application, resulting in a denial of service.
Weakness: CWE-400
Which versions are affected by CVE-2020-36872?
How do I fix CVE-2020-36872?
No fix has been published for CVE-2020-36872 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-2020-36872 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2020-36872 exists.
Sources
Also known as GHSA-3v4j-cjvq-5p59.