In QEMU 4.1.0, an out-of-bounds read flaw was found in the ATI VGA implementation. It occurs in the ati_cursor_define() routine while handling MMIO write operations through the ati_mm_write() callback. A malicious guest could abuse this flaw to crash the QEMU process, resulting in a denial of service.
https://security.netapp.com/advisory/ntap-20210205-0003/
https://git.qemu.org/?p=qemu.git%3Ba=commit%3Bh=aab0e2a661b2b6bf7915c0aefe807fb60d6d9d13