Vim is an open source, command line text editor. A segmentation fault was found in Vim before 9.1.1043. In silent Ex mode (-s -e), Vim typically doesn't show a screen and just operates silently in batch mode. However, it is still possible to trigger the function that handles the scrolling of a gui version of Vim by feeding some binary characters to Vim. The function that handles the scrolling however may be triggering a redraw, which will access the ScreenLines pointer, even so this variable hasn't been allocated (since there is no screen). This vulnerability is fixed in 9.1.1043.
The product writes data past the end, or before the beginning, of the intended buffer.