ReadXBMImage in coders/xbm.c in ImageMagick before 7.0.8-9 leaves data uninitialized when processing an XBM file that has a negative pixel value. If the affected code is used as a library loaded into a process that includes sensitive information, that information sometimes can be leaked via the image data.
https://www.exploit-db.com/exploits/45890/
https://usn.ubuntu.com/4034-1/
https://usn.ubuntu.com/3785-1/
https://github.com/ImageMagick/ImageMagick/commit/216d117f05bff87b9dc4db55a1b1fadb38bcb786