A memory leakage flaw was found in the way VNC display driver of QEMU handled connection disconnect, when ZRLE, Tight encoding is enabled. It creates two vncState objects, one of which allocates memory for Zlib's data object. This allocated memory is not free'd upon disconnection resulting in the said memory leakage issue. A user able to connect to the VNC server could use this flaw to leak host memory leading to a potential DoS scenario.
Created qemu tracking bugs for this issue:
Affects: fedora-all [bug 1810391]
This flaw did not affect the versions of `qemu-kvm` as shipped with Red Hat Enterprise Linux 6 as they did not include the vulnerable code.