The Network Block Device (NBD) server in Quick Emulator (QEMU) before 2.11 is vulnerable to a denial of service issue. It could occur if a client sent large option requests, making the server waste CPU time on reading up to 4GB per request. A client could use this flaw to keep the NBD server from serving other requests, resulting in DoS.

An assertion-failure flaw was found in Qemu before 2.10.1, in the Network Block Device (NBD) server's initial connection negotiation, where the I/O coroutine was undefined. This could crash the qemu-nbd server if a client sent unexpected data during connection negotiation. A remote user or process could use this flaw to crash the qemu-nbd server resulting in denial of service.

qmp_guest_file_read in qga/commands-posix.c and qga/commands-win32.c in qemu-ga (aka QEMU Guest Agent) in QEMU 2.12.50 has an integer overflow causing a g_malloc0() call to trigger a segmentation fault when trying to allocate a large memory chunk. The vulnerability can be exploited by sending a crafted QMP command (including guest-file-read with a large count value) to the agent via the listening socket.

m_cat in slirp/mbuf.c in Qemu has a heap-based buffer overflow via incoming fragmented datagrams.

Quick Emulator (aka QEMU), when built with the Cirrus CLGD 54xx VGA Emulator support, allows local guest OS privileged users to cause a denial of service (out-of-bounds access and QEMU process crash) by leveraging incorrect region calculation when updating VGA display.

The load_multiboot function in hw/i386/multiboot.c in Quick Emulator (aka QEMU) allows local guest OS users to execute arbitrary code on the QEMU host via a mh_load_end_addr value greater than mh_bss_end_addr, which triggers an out-of-bounds read or write memory access.

Integer overflow in the macro ROUND_UP (n, d) in Quick Emulator (Qemu) allows a user to cause a denial of service (Qemu process crash).

The vga_draw_text function in Qemu allows local OS guest privileged users to cause a denial of service (out-of-bounds read and QEMU process crash) by leveraging improper memory address validation.

VNC server implementation in Quick Emulator (QEMU) 2.11.0 and older was found to be vulnerable to an unbounded memory allocation issue, as it did not throttle the framebuffer updates sent to its client. If the client did not consume these updates, VNC server allocates growing memory to hold onto this data. A malicious remote VNC client could use this flaw to cause DoS to the server host.

The Virtio Vring implementation in QEMU allows local OS guest users to cause a denial of service (divide-by-zero error and QEMU process crash) by unsetting vring alignment while updating Virtio rings.

hw/input/ps2.c in Qemu does not validate 'rptr' and 'count' values during guest migration, leading to out-of-bounds access.

The mode4and5 write functions in hw/display/cirrus_vga.c in Qemu allow local OS guest privileged users to cause a denial of service (out-of-bounds write access and Qemu process crash) via vectors related to dst calculation.

Qemu through 2.10.0 allows remote attackers to cause a memory leak by triggering slow data-channel read operations, related to io/channel-websock.c.

Integer overflow in the load_multiboot function in hw/i386/multiboot.c in QEMU (aka Quick Emulator) allows local guest OS users to execute arbitrary code on the host via crafted multiboot header address values, which trigger an out-of-bounds write.

Use-after-free vulnerability in the sofree function in slirp/socket.c in QEMU (aka Quick Emulator) allows attackers to cause a denial of service (QEMU instance crash) by leveraging failure to properly clear ifq_so from pending packets.

QEMU (aka Quick Emulator), when built with the VGA display emulator support, allows local guest OS privileged users to cause a denial of service (out-of-bounds read and QEMU process crash) via vectors involving display update.

The dhcp_decode function in slirp/bootp.c in QEMU (aka Quick Emulator) allows local guest OS users to cause a denial of service (out-of-bounds read and QEMU process crash) via a crafted DHCP options string.

Stack-based buffer overflow in the vrend_decode_set_framebuffer_state function in vrend_decode.c in virglrenderer before 926b9b3460a48f6454d8bbe9e44313d86a65447f, as used in Quick Emulator (QEMU), allows a local guest users to cause a denial of service (application crash) via the "nr_cbufs" argument.