The specific fields of CGI interface of some Dahua products are not strictly verified, an attacker can cause a buffer overflow by constructing malicious packets. Affected products include: IPC-HDW1X2X,IPC-HFW1X2X,IPC-HDW2X2X,IPC-HFW2X2X,IPC-HDW4X2X,IPC-HFW4X2X,IPC-HDBW4X2X,IPC-HDW5X2X,IPC-HFW5X2X for versions which Build time is before August 18, 2019.
https://www.dahuasecurity.com/support/cybersecurity/details/637