A security issue fixed upstream in flatpak has been announced: http://openwall.com/lists/oss-security/2017/06/22/13 The issue is fixed in 0.9.6.
Debian has issued an advisory for this on June 22: https://www.debian.org/security/2017/dsa-3895
Freeze push request sent for ostree (to 2017.7) and flatpak (to 0.9.6) to resolve this.
flatpak-0.9.6-2.mga6 uploaded for Cauldron. Thanks.
Resolution: (none) => FIXEDStatus: NEW => RESOLVED