An issue was discovered in Xen through 4.11.x. ARM never properly implemented grant table v2, either in the hypervisor or in Linux. Unfortunately, an ARM guest can still request v2 grant tables; they will simply not be properly set up, resulting in subsequent grant-related hypercalls hitting BUG() checks. An unprivileged guest can cause a BUG() check in the hypervisor, resulting in a denial-of-service (crash).

The mptsas_process_scsi_io_request function in QEMU (aka Quick Emulator), when built with LSI SAS1068 Host Bus emulation support, allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) via vectors involving MPTSASRequest objects.

Use-after-free vulnerability in the vmxnet3_io_bar0_write function in hw/net/vmxnet3.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (QEMU instance crash) by leveraging failure to check if the device is active.

In the Linux kernel, the following vulnerability has been resolved: nvme-fc: do not wait in vain when unloading module The module exit path has race between deleting all controllers and freeing 'left over IDs'. To prevent double free a synchronization between nvme_delete_ctrl and ida_destroy has been added by the initial commit. There is some logic around trying to prevent from hanging forever in wait_for_completion, though it does not handling all cases. E.g. blktests is able to reproduce the situation where the module unload hangs forever. If we completely rely on the cleanup code executed from the nvme_delete_ctrl path, all IDs will be freed eventually. This makes calling ida_destroy unnecessary. We only have to ensure that all nvme_delete_ctrl code has been executed before we leave nvme_fc_exit_module. This is done by flushing the nvme_delete_wq workqueue. While at it, remove the unused nvme_fc_wq workqueue too.

hw/scsi/vmw_pvscsi.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (out-of-bounds access or infinite loop, and QEMU process crash) via a crafted page count for descriptor rings.

The pvscsi_convert_sglist function in hw/scsi/vmw_pvscsi.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (infinite loop and QEMU process crash) by leveraging an incorrect cast.

fs/fcntl.c in the "aufs 3.2.x+setfl-debian" patch in the linux-image package 3.2.0-4 (kernel 3.2.81-1) in Debian wheezy mishandles F_SETFL fcntl calls on directories, which allows local users to cause a denial of service (NULL pointer dereference and system crash) via standard filesystem operations, as demonstrated by scp from an AUFS filesystem.

The virtqueue_map_desc function in hw/virtio/virtio.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (infinite loop and QEMU process crash) via a zero length for the descriptor buffer.

The vmsvga_fifo_run function in hw/display/vmware_vga.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) via vectors related to cursor.mask[] and cursor.image[] array sizes when processing a DEFINE_CURSOR svga command.

The get_cmd function in hw/scsi/esp.c in QEMU might allow local guest OS administrators to cause a denial of service (out-of-bounds write and QEMU process crash) via vectors related to reading from the information transfer buffer in non-DMA mode.

The virtqueue_pop function in hw/virtio/virtio.c in QEMU allows local guest OS administrators to cause a denial of service (memory consumption and QEMU process crash) by submitting requests without waiting for completion.

The mptsas_fetch_requests function in hw/scsi/mptsas.c in QEMU (aka Quick Emulator) allows local guest OS administrators to cause a denial of service (infinite loop, and CPU consumption or QEMU process crash) via vectors involving s->state.

The ehci_advance_state function in hw/usb/hcd-ehci.c in QEMU allows local guest OS administrators to cause a denial of service (infinite loop and CPU consumption) via a circular split isochronous transfer descriptor (siTD) list, a related issue to CVE-2015-8558.

An issue was discovered in Xen through 4.14.x. A guest may access xenstore paths via absolute paths containing a full pathname, or via a relative path, which implicitly includes /local/domain/$DOMID for their own domain id. Management tools must access paths in guests' namespaces, necessarily using absolute paths. oxenstored imposes a pathname limit that is applied solely to the relative or absolute path specified by the client. Therefore, a guest can create paths in its own namespace which are too long for management tools to access. Depending on the toolstack in use, a malicious guest administrator might cause some management tools and debugging operations to fail. For example, a guest administrator can cause "xenstore-ls -r" to fail. However, a guest administrator cannot prevent the host administrator from tearing down the domain. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable.

The resv_map_release function in mm/hugetlb.c in the Linux kernel through 4.15.7 allows local users to cause a denial of service (BUG) via a crafted application that makes mmap system calls and has a large pgoff argument to the remap_file_pages system call.

An issue was discovered in Xen through 4.14.x. Recording of the per-vCPU control block mapping maintained by Xen and that of pointers into the control block is reversed. The consumer assumes, seeing the former initialized, that the latter are also ready for use. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system.

An issue was discovered in Xen through 4.10.x. Certain PV MMU operations may take a long time to process. For that reason Xen explicitly checks for the need to preempt the current vCPU at certain points. A few rarely taken code paths did bypass such checks. By suitably enforcing the conditions through its own page table contents, a malicious guest may cause such bypasses to be used for an unbounded number of iterations. A malicious or buggy PV guest may cause a Denial of Service (DoS) affecting the entire host. Specifically, it may prevent use of a physical CPU for an indeterminate period of time. All Xen versions from 3.4 onwards are vulnerable. Xen versions 3.3 and earlier are vulnerable to an even wider class of attacks, due to them lacking preemption checks altogether in the affected code paths. Only x86 systems are affected. ARM systems are not affected. Only multi-vCPU x86 PV guests can leverage the vulnerability. x86 HVM or PVH guests as well as x86 single-vCPU PV ones cannot leverage the vulnerability.

A flaw memory leak in the Linux kernel performance monitoring subsystem was found in the way if using PERF_EVENT_IOC_SET_FILTER. A local user could use this flaw to starve the resources causing denial of service.

Improper invalidation for page table updates by a virtual guest operating system for multiple Intel(R) Processors may allow an authenticated user to potentially enable denial of service of the host system via local access.

A flaw was found in the Linux kernel's ext4 filesystem. A local user can cause an out-of-bound write in in fs/jbd2/transaction.c code, a denial of service, and a system crash by unmounting a crafted ext4 filesystem image.

The xfs_bmap_extents_to_btree function in fs/xfs/libxfs/xfs_bmap.c in the Linux kernel through 4.16.3 allows local users to cause a denial of service (xfs_bmapi_write NULL pointer dereference) via a crafted xfs image.

An issue was discovered in Xen through 4.10.x allowing x86 PV guest OS users to cause a denial of service (out-of-bounds zero write and hypervisor crash) via unexpected INT 80 processing, because of an incorrect fix for CVE-2017-5754.

A flaw was found in Linux kernel in the ext4 filesystem code. A use-after-free is possible in ext4_ext_remove_space() function when mounting and operating a crafted ext4 image.

The Linux Kernel version 3.18 contains a dangerous feature vulnerability in modify_user_hw_breakpoint() that can result in crash and possibly memory corruption. This attack appear to be exploitable via local code execution and the ability to use ptrace. This vulnerability appears to have been fixed in git commit f67b15037a7a50c57f72e69a6d59941ad90a0f0f.

An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. Guest OS users can cause a denial of service (host OS hang) via a high rate of events to dom0, aka CID-e99502f76271.

An issue was discovered in drivers/accessibility/speakup/spk_ttyio.c in the Linux kernel through 5.9.9. Local attackers on systems with the speakup driver could cause a local denial of service attack, aka CID-d41227544427. This occurs because of an invalid free when the line discipline is used more than once.

Memory leak in hw/watchdog/wdt_i6300esb.c in QEMU (aka Quick Emulator) allows local guest OS privileged users to cause a denial of service (host memory consumption and QEMU process crash) via a large number of device unplug operations.

net/sctp/sm_sideeffect.c in the Linux kernel before 4.3 does not properly manage the relationship between a lock and a socket, which allows local users to cause a denial of service (deadlock) via a crafted sctp_accept call.

The __rds_conn_create function in net/rds/connection.c in the Linux kernel through 4.2.3 allows local users to cause a denial of service (NULL pointer dereference and system crash) or possibly have unspecified other impact by using a socket that was not properly bound.

An issue was discovered in MediaWiki before 1.35.6, 1.36.x before 1.36.4, and 1.37.x before 1.37.2. Users with the editinterface permission can trigger infinite recursion, because a bare local interwiki is mishandled for the mainpage message.

The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a denial of service (host OS panic or hang) by triggering many #AC (aka Alignment Check) exceptions, related to svm.c and vmx.c.

Memory leak in the hwsim_new_radio_nl function in drivers/net/wireless/mac80211_hwsim.c in the Linux kernel through 4.15.9 allows local users to cause a denial of service (memory consumption) by triggering an out-of-array error case.

The ping_unhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3 does not initialize a certain list data structure during an unhash operation, which allows local users to gain privileges or cause a denial of service (use-after-free and system crash) by leveraging the ability to make a SOCK_DGRAM socket system call for the IPPROTO_ICMP or IPPROTO_ICMPV6 protocol, and then making a connect system call after a disconnect.

The (1) BMDMA and (2) AHCI HBA interfaces in the IDE functionality in QEMU 1.0 through 2.1.3 have multiple interpretations of a function's return value, which allows guest OS users to cause a host OS denial of service (memory consumption or infinite loop, and system crash) via a PRDT with zero complete sectors, related to the bmdma_prepare_buf and ahci_dma_prepare_buf functions.

The acceleration support for the "REP MOVS" instruction in Xen 4.4.x, 3.2.x, and earlier lacks properly bounds checking for memory mapped I/O (MMIO) emulated in the hypervisor, which allows local HVM guests to cause a denial of service (host crash) via unspecified vectors.

In the Linux kernel through 4.14.13, the rds_cmsg_atomic function in net/rds/rdma.c mishandles cases where page pinning fails or an invalid address is supplied, leading to an rds_atomic_free_op NULL pointer dereference.

Memory leak in the irda_bind function in net/irda/af_irda.c and later in drivers/staging/irda/net/af_irda.c in the Linux kernel before 4.17 allows local users to cause a denial of service (memory consumption) by repeatedly binding an AF_IRDA socket.

ati-vga in hw/display/ati.c in QEMU 4.2.0 allows guest OS users to trigger infinite recursion via a crafted mm_index value during an ati_mm_read or ati_mm_write call.