Uninitialized memory disclosure when rendering PNG files with and empty zlib object
When opening the following image, EoG displays "random" pixels, probably as a result of using uninitialized memory:
https://github.com/0xcite/fingerping/blob/master/images/idat_empty_zlib_object.png
To reproduce the issue it is recommended to open a number of properly formatted images along with the above one and browse back and forth between them. When displaying idat_empty_zlib_object.png a mix of parts of previous images is displayed.
Tested with 3.18.2-1ubuntu2.1. I doubt that this has any security implications, considering the typical use of EoG.