Heap-based buffer overflow in the Cirrus VGA implementation in (1) KVM before kvm-82 and (2) QEMU on Debian GNU/Linux and Ubuntu might allow local users to gain privileges by using the VNC console for a connection, aka the LGD-54XX "bitblt" heap overflow. NOTE: this issue exists because of an incorrect fix for CVE-2007-1320.

The x86 emulator in KVM 83, when a guest is configured for Symmetric Multiprocessing (SMP), does not use the Current Privilege Level (CPL) and I/O Privilege Level (IOPL) to restrict instruction execution, which allows guest OS users to cause a denial of service (guest OS crash) or gain privileges on the guest OS by leveraging access to a (1) IO port or (2) MMIO region, and replacing an instruction in between emulator entry and instruction fetch, a related issue to CVE-2010-0298.

The x86 emulator in KVM 83, when a guest is configured for Symmetric Multiprocessing (SMP), does not properly restrict writing of segment selectors to segment registers, which might allow guest OS users to cause a denial of service (guest OS crash) or gain privileges on the guest OS by leveraging access to a (1) IO port or (2) MMIO region, and replacing an instruction in between emulator entry and instruction fetch.