FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. In affected versions a malicious server might trigger out of bound writes in a connected client. Connections using GDI or SurfaceCommands to send graphics updates to the client might send `0` width/height or out of bound rectangles to trigger out of bound writes. With `0` width or heigth the memory allocation will be `0` but the missing bounds checks allow writing to the pointer at this (not allocated) region. This issue has been patched in FreeRDP 2.4.1.
In FreeRDP before 2.4.0 on Windows, wf_cliprdr_server_file_contents_request in client/Windows/wf_cliprdr.c has missing input checks for a FILECONTENTS_SIZE File Contents Request PDU.
In FreeRDP before 2.4.0 on Windows, wf_cliprdr_server_file_contents_request in client/Windows/wf_cliprdr.c has missing input checks for a FILECONTENTS_RANGE File Contents Request PDU.
In FreeRDP less than or equal to 2.1.2, an integer overflow exists due to missing input sanitation in rdpegfx channel. All FreeRDP clients are affected. The input rectangles from the server are not checked against local surface coordinates and blindly accepted. A malicious server can send data that will crash the client later on (invalid length arguments to a `memcpy`) This has been fixed in 2.2.0. As a workaround, stop using command line arguments /gfx, /gfx-h264 and /network:auto