ASUS RT-AC68U, RT-AC66R, RT-AC66U, RT-AC56R, RT-AC56U, RT-N66R, RT-N66U, RT-N56R, RT-N56U, and possibly other RT-series routers before firmware 3.0.0.4.376.x do not verify the integrity of firmware (1) update information or (2) downloaded updates, which allows man-in-the-middle (MITM) attackers to execute arbitrary code via a crafted image.
https://support.t-mobile.com/docs/DOC-21994
https://exchange.xforce.ibmcloud.com/vulnerabilities/98316
https://euvd.enisa.europa.eu/vulnerability/EUVD-2014-2746
http://www.securityfocus.com/bid/70791
http://seclists.org/fulldisclosure/2014/Oct/122
http://packetstormsecurity.com/files/128904/ASUS-Router-Man-In-The-Middle.html
http://dnlongen.blogspot.com/2014/10/CVE-2014-2718-Asus-RT-MITM.html