Integer Overflow or Wraparound
In RestoreMSCWarning() of /coders/pdf.c there are several areas where calls to GetPixelIndex() could result in values outside the range of representable for the unsigned char type. The patch casts the return value of GetPixelIndex() to ssize_t type to avoid this bug. This undefined behavior could be triggered when ImageMagick processes a crafted pdf file. Red Hat Product Security marked this as Low severity because although it could potentially lead to an impact to application availability, no specific impact was demonstrated in this case. This flaw affects ImageMagick versions prior to 7.0.9-0 and ImageMagick6 versions prior to 6.9.10-69.
CWE-190 - Integer Overflow or Wraparound
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.