Two vulnerabilities have been identified in Qt for Android which could be used by a malicious application to hijack an existing Qt for Android application on the same device. The vulnerabilities in question were found by Satoru Nagaoka from Cyber Defense Institute, Inc., and have been assigned the following vulnerability IDs: JVN#27342829 and JVN#67389262.
These vulnerabilities have subsequently been fixed in Qt 5.9 as well as the Qt 5.6 branch of Qt. Qt 5.9.3, which was released today, contains all required patches.
For users of Qt 5.7 or Qt 5.8, we have prepared patch sets which can be applied to the source tree in order to fix these issues. They can be downloaded from Qt Account or by accessing these links: 5.6.3, 5.7.1 and 5.8.0. The patches are organized in qtbase/ and qttools/ subfolders for the code repositories where changes are needed.
Thanks to Bogdan Vatra from KDAB for supplying the necessary patches on short notice.
(updated 2017-12-11: added links to JVN database entries and corrected reporter name.)