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.
https://www.debian.org/security/2020/dsa-4665
https://usn.ubuntu.com/4372-1/
https://lists.debian.org/debian-lts-announce/2020/07/msg00020.html
https://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=6bf21f3d83e95bcc4ba35a7a07cc6655e8b010b0
http://www.openwall.com/lists/oss-security/2020/03/05/1
http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00007.html