GraphicsMagick CVE request: 8BIM/8BIMW unsigned underflow leads to heap overflow

[Bob Friesenhahn <bfriesen () simple dallas tx us>]

Today we received a report from Marco Grassi about a heap overflow in 
the 8BIM reader.  8BIM is a metadata chunk often attached to JPEG 
files.

After investigation it was found that there was a small unsigned 
overflow leading to a huge size value, which then resulted in a heap 
overflow (causing a crash).

We believe that this issue exists in all GraphicsMagick releases to 
date (including 1.3.25).

The fix to this may be found in GraphicsMagick Mercurial at 
"https://sourceforge.net/p/graphicsmagick/code/ci/5c7b6d6094a25e99c57f8b18343914ebfd8213ef/";.

Bob
--
Bob Friesenhahn
bfriesen () simple dallas tx us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/