Mjolnir is a moderation tool for Matrix. Mjolnir v1.9.0 responds to management commands from any room the bot is member of. This can allow users who aren't operators of the bot to use the bot's functions, including server administration components if enabled. Version 1.9.1 reverts the feature that introduced the bug, and version 1.9.2 reintroduces the feature safely. Downgrading to version 1.8.3 is recommended if upgrading to 1.9.1 or higher isn't possible.
The product uses security features in a way that prevents the product's administrator from tailoring security settings to reflect the environment in which the product is being used. This introduces resultant weaknesses or prevents it from operating at a level of security that is desired by the administrator.