File Extension CDR
File extension CDR is used by CorelDraw vector editing software developed by Corel Corporation. CDR files could be opened by CorelDraw application. Only Windows version of CorelDraw is currently available. Other applications which could open CDR files include: Adobe Illustrator, Corel PaintShop Pro, Corel WordPerfect Office, Inkscape.
Starting with version X4 (14) CDR file format was changed to a ZIPed directory with data in XML files and, riffdata.cdr file and root.dat file. So if you rename CDR file to ZIP it is possible to extract it and view some of the information inside without opening CorelDraw.
Besides CDR CorelDraw also supports CorelDraw Compressed (CDX), CorelDraw Presentation Exchange (CMX) and CorelDraw Template (CDT)
Also you can use libcdr development library to parse CDR files and get vector data from it.