The kernel in Apple iOS before 9.3.5 allows attackers to obtain sensitive information from memory via a crafted app.
http://lists.apple.com/archives/security-announce/2016/Sep/msg00005.html
http://lists.apple.com/archives/security-announce/2016/Aug/msg00000.html
https://github.com/liangle1986126z/jndok
https://github.com/tomitokics/br0ke
https://github.com/Cryptiiiic/skybreak
https://github.com/jndok/PegasusX
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-4655
https://support.apple.com/HT207145
https://support.apple.com/HT207107
https://blog.lookout.com/blog/2016/08/25/trident-pegasus/
http://www.securitytracker.com/id/1036694