static int UnpackWPGRaster(Image *image,int bpp,ExceptionInfo *exception)
{
  int
    x,
    y,
    i;

  unsigned char
    bbuf,
    *BImgBuff,
    RunCount;

  ssize_t
    ldblk;

  x=0;
  y=0;

  ldblk=(ssize_t) ((bpp*image->columns+7)/8);
  BImgBuff=(unsigned char *) AcquireQuantumMemory((size_t) ldblk,
    8*sizeof(*BImgBuff));
  if(BImgBuff==NULL) return(-2);

  while(y<(ssize_t) image->rows)
    {
      int
        c;

      c=ReadBlobByte(image);
      if (c == EOF)
        break;
      bbuf=(unsigned char) c;
      RunCount=bbuf & 0x7F;
      if(bbuf & 0x80)
        {
          if(RunCount)  /* repeat next byte runcount * */
            {
              bbuf=ReadBlobByte(image);
              for(i=0;i<(int) RunCount;i++) InsertByte(bbuf);
            }
          else {  /* read next byte as RunCount; repeat 0xFF runcount* */
            c=ReadBlobByte(image);
            if (c < 0)
              break;
            RunCount=(unsigned char) c;
            for(i=0;i<(int) RunCount;i++) InsertByte(0xFF);
          }
        }
      else {
        if(RunCount)   /* next runcount byte are readed directly */
          {
            for(i=0;i < (int) RunCount;i++)
              {
                bbuf=ReadBlobByte(image);
                InsertByte(bbuf);
              }
          }
        else {  /* repeat previous line runcount* */
          c=ReadBlobByte(image);
          if (c < 0)
            break;
          RunCount=(unsigned char) c;
          if(x) {    /* attempt to duplicate row from x position: */
            /* I do not know what to do here */
            BImgBuff=(unsigned char *) RelinquishMagickMemory(BImgBuff);
            return(-3);
          }
          for(i=0;i < (int) RunCount;i++)
            {
              x=0;
              y++;    /* Here I need to duplicate previous row RUNCOUNT* */
              if(y<2) continue;
              if(y>(ssize_t) image->rows)
                {
                  BImgBuff=(unsigned char *) RelinquishMagickMemory(BImgBuff);
                  return(-4);
                }
              InsertRow(image,BImgBuff,y-1,bpp,exception);
            }
        }
      }
      if (EOFBlob(image) != MagickFalse)
        break;
    }
  BImgBuff=(unsigned char *) RelinquishMagickMemory(BImgBuff);
  return(y <(ssize_t) image->rows ? -5 : 0);
}

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.