QEMU (aka Quick Emulator) built with the USB EHCI emulation support is vulnerable to a null pointer dereference flaw. It could occur when an application attempts to write to EHCI capabilities registers. A privileged user inside quest could use this flaw to crash the QEMU process instance resulting in DoS.

Integer overflow in the VGA module in QEMU allows local guest OS users to cause a denial of service (out-of-bounds read and QEMU process crash) by editing VGA registers in VBE mode.

The VGA module in QEMU improperly performs bounds checking on banked access to video memory, which allows local guest OS administrators to execute arbitrary code on the host by changing access modes after setting the bank register, aka the "Dark Portal" issue.