The DrawDashPolygon function in MagickCore/draw.c in ImageMagick before 6.9.4-0 and 7.x before 7.0.1-2 mishandles calculations of certain vertices integer data, which allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a crafted file.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.