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. https://nvd.nist.gov/vuln/detail/CVE-2018-12617
