An integer overflow was found in QEMU 4.0.1 through 4.2.0 in the way it implemented ATI VGA emulation. This flaw occurs in the ati_2d_blt() routine in hw/display/ati-2d.c 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.

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