A weakness has been identified in stamparm maltrail up to 3.0.1. This vulnerability affects the function blacklist of the file core/httpd.py of the component Blacklist Endpoint. Executing a manipulation can lead to missing authentication. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 3.1 is able to resolve this issue. This patch is called d95868dff3da4d3bd4f942837a26cb7c73a797ae. It is suggested to upgrade the affected component. The vendor fixed the issue the same day it was reported, in version 3.1, by gating the endpoint on an authenticated session or the new BlacklistALLOWLIST option.