FreeRDP is a free implementation of the Remote Desktop Protocol. FreeRDP based clients that use a version of FreeRDP prior to 3.5.0 or 2.11.6 and have connections to servers using the NSC codec are vulnerable to integer underflow. Versions 3.5.0 and 2.11.6 patch the issue. As a workaround, do not use the NSC codec (e.g. use -nsc).
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.