CVE-2017-7475 Cairo-1.15.4 Denial-of-Service Attack due to Logical Problem in Program

[李琪 <pjqruc () gmail com>]

Hello,

## Overview
I and my colleague have found a vulnerability of Cairo-1.15.4 when fuzzing
HarfBuzz with AFL.
Cairo is a 2d graphics library, and HarBuzz is an OpenType text shaping
engine which contains a tool named *hb-view* to give a graphical view of
text using Cairo with a font provided by user.
Owing to logical problem in program, the crash happens during null pointer
deference and the vulnerability will cause a denial-of-service attack with
a crafted font file.

## Note
I have reported this issue to cairo and here is the link:
https://bugs.freedesktop.org/show_bug.cgi?id=100763.

When I disclosure to Red Hat Product Security, they suggest me to use
CVE-2017-7475 for this issue and I have communicated this number to
upstream.


Best Regards,

--
Jiaqi Peng, Bingchang Liu @ VARAS of IIE