Oracle Linux: CVE-2019-20382: ELSA-2020-2774: virt:ol security update (IMPORTANT) (Multiple Advisories)

QEMU 4.1.0 has a memory leak in zrle_compress_data in ui/vnc-enc-zrle.c during a VNC disconnect operation because libz is misused, resulting in a situation where memory allocated in deflateInit2 is not freed in deflateEnd.
A memory leakage flaw was found in the way the VNC display driver of QEMU handled the connection disconnect when ZRLE and Tight encoding are enabled. Two VncState objects are created, and one allocates memory for the Zlib's data object. This allocated memory is not freed upon disconnection, resulting in a memory leak. An attacker able to connect to the VNC server could use this flaw to leak host memory, leading to a potential denial of service.