DSA-4454-1

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

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.

A flaw was found in qemu Media Transfer Protocol (MTP). The code opening files in usb_mtp_get_object and usb_mtp_get_partial_object and directories in usb_mtp_object_readdir doesn't consider that the underlying filesystem may have changed since the time lstat(2) was called in usb_mtp_object_alloc, a classical TOCTTOU problem. An attacker with write access to the host filesystem shared with a guest can use this property to navigate the host filesystem in the context of the QEMU process and read any file the QEMU process has access to. Access to the filesystem may be local or via a network share protocol such as CIFS.

Qemu has a Buffer Overflow in rtl8139_do_receive in hw/net/rtl8139.c because an incorrect integer data type is used.

In Qemu 3.0.0, lsi_do_msgin in hw/scsi/lsi53c895a.c allows out-of-bounds access by triggering an invalid msg_len value.

The pnv_lpc_do_eccb function in hw/ppc/pnv_lpc.c in Qemu before 3.1 allows out-of-bounds write or read access to PowerNV memory.

hw/9pfs/cofile.c and hw/9pfs/9p.c in QEMU can modify an fid path while it is being accessed by a second thread, leading to (for example) a use-after-free outcome.

v9fs_wstat in hw/9pfs/9p.c in QEMU allows guest OS users to cause a denial of service (crash) because of a race condition during file renaming.

interface_release_resource in hw/display/qxl.c in QEMU 3.1.x through 4.0.0 has a NULL pointer dereference.

QEMU, through version 2.10 and through version 3.1.0, is vulnerable to an out-of-bounds read of up to 128 bytes in the hw/i2c/i2c-ddc.c:i2c_ddc() function. A local attacker with permission to execute i2c commands could exploit this to read stack memory of the qemu process on the host.

In QEMU 3.0.0, tcp_emu in slirp/tcp_subr.c has a heap-based buffer overflow.

tcp_emu in slirp/tcp_subr.c (aka slirp/src/tcp_subr.c) in QEMU 3.0.0 uses uninitialized data in an snprintf call, leading to Information disclosure.