A double free flaw was found in the way TigerVNC handled ClientFence messages. A remote, authenticated attacker could use this flaw to make Xvnc crash by sending specially crafted ClientFence messages, resulting in denial of service.
In TigerVNC (VNCSConnectionST.cxx VNCSConnectionST::fence), an authenticated client can cause a double free, leading to a crash of the TigerVNC server.
Created tigervnc tracking bugs for this issue:
Affects: fedora-all [bug 1438704]
This issue has been addressed in the following products:
Red Hat Enterprise Linux 7
Via RHSA-2017:2000 https://access.redhat.com/errata/RHSA-2017:2000