In the Linux kernel before 5.1.13, there is a memory leak in drivers/scsi/libsas/sas_expander.c when SAS expander discovery fails. This will cause a BUG and denial of service.

Quick emulator (Qemu) built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to a divide by zero issue. It could occur while copying VGA data when cirrus graphics mode was set to be VGA. A privileged user inside guest could use this flaw to crash the Qemu process instance on the host, resulting in DoS.

Memory leak in hw/9pfs/9p-handle.c in QEMU (aka Quick Emulator) allows local privileged guest OS users to cause a denial of service (host memory consumption and possibly QEMU process crash) by leveraging a missing cleanup operation in the handle backend.

Memory leak in hw/9pfs/9p-proxy.c in QEMU (aka Quick Emulator) allows local privileged guest OS users to cause a denial of service (host memory consumption and possibly QEMU process crash) by leveraging a missing cleanup operation in the proxy backend.

Race condition in the store_int_with_restart() function in arch/x86/kernel/cpu/mcheck/mce.c in the Linux kernel through 4.15.7 allows local users to cause a denial of service (panic) by leveraging root access to write to the check_interval file in a /sys/devices/system/machinecheck/machinecheck<cpu number> directory. NOTE: a third party has indicated that this report is not security relevant

Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)

An issue was discovered in Xen through 4.11.x allowing 64-bit PV guest OS users to cause a denial of service (host OS crash) because #GP[0] can occur after a non-canonical address is passed to the TLB flushing code. NOTE: this issue exists because of an incorrect CVE-2017-5754 (aka Meltdown) mitigation.

The ahci_commit_buf function in ide/ahci.c in QEMU allows attackers to cause a denial of service (NULL dereference) when the command header 'ad->cur_cmd' is null.

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

The p2m_teardown function in arch/arm/p2m.c in Xen 4.4.x through 4.6.x allows local guest OS users with access to the driver domain to cause a denial of service (NULL pointer dereference and host OS crash) by creating concurrent domains and holding references to them, related to VMID exhaustion.

QEMU, when built with the Pseudo Random Number Generator (PRNG) back-end support, allows local guest OS users to cause a denial of service (process crash) via an entropy request, which triggers arbitrary stack based allocation and memory corruption.

x86/HVM pinned cache attributes mis-handling T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] To allow cachability control for HVM guests with passed through devices, an interface exists to explicitly override defaults which would otherwise be put in place. While not exposed to the affected guests themselves, the interface specifically exists for domains controlling such guests. This interface may therefore be used by not fully privileged entities, e.g. qemu running deprivileged in Dom0 or qemu running in a so called stub-domain. With this exposure it is an issue that - the number of the such controlled regions was unbounded (CVE-2022-42333), - installation and removal of such regions was not properly serialized (CVE-2022-42334).

Xenstore: Guests can crash xenstored via exhausting the stack Xenstored is using recursion for some Xenstore operations (e.g. for deleting a sub-tree of Xenstore nodes). With sufficiently deep nesting levels this can result in stack exhaustion on xenstored, leading to a crash of xenstored.

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

Xenstore: Guests can cause Xenstore to not free temporary memory When working on a request of a guest, xenstored might need to allocate quite large amounts of memory temporarily. This memory is freed only after the request has been finished completely. A request is regarded to be finished only after the guest has read the response message of the request from the ring page. Thus a guest not reading the response can cause xenstored to not free the temporary memory. This can result in memory shortages causing Denial of Service (DoS) of xenstored.

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

The paging_invlpg function in include/asm-x86/paging.h in Xen 3.3.x through 4.6.x, when using shadow mode paging or nested virtualization is enabled, allows local HVM guest users to cause a denial of service (host crash) via a non-canonical guest address in an INVVPID instruction, which triggers a hypervisor bug check.

Guests can trigger NIC interface reset/abort/crash via netback It is possible for a guest to trigger a NIC interface reset/abort/crash in a Linux based network backend by sending certain kinds of packets. It appears to be an (unwritten?) assumption in the rest of the Linux network stack that packet protocol headers are all contained within the linear section of the SKB and some NICs behave badly if this is not the case. This has been reported to occur with Cisco (enic) and Broadcom NetXtrem II BCM5780 (bnx2x) though it may be an issue with other NICs/drivers as well. In case the frontend is sending requests with split headers, netback will forward those violating above mentioned assumption to the networking core, resulting in said misbehavior.

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.

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

An issue was discovered in the Linux kernel through 5.9.1, as used with Xen through 4.14.x. drivers/xen/events/events_base.c allows event-channel removal during the event-handling loop (a race condition). This can cause a use-after-free or NULL pointer dereference, as demonstrated by a dom0 crash via events for an in-reconfiguration paravirtualized device, aka CID-073d0552ead5.

Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction

In the Linux kernel before 4.9.3, fs/xfs/xfs_aops.c allows local users to cause a denial of service (system crash) because there is a race condition between direct and memory-mapped I/O (associated with a hole) that is handled with BUG_ON instead of an I/O failure.

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly release locks, which might allow guest OS administrators to cause a denial of service (deadlock or host crash) via unspecified vectors, related to XENMEM_exchange error handling.

Race condition in the relinquish_memory function in arch/arm/domain.c in Xen 4.6.x and earlier allows local domains with partial management control to cause a denial of service (host crash) via vectors involving the destruction of a domain and using XENMEM_decrease_reservation to reduce the memory of the domain.

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 #DB (aka Debug) exceptions, related to svm.c.

The memory_exchange function in common/memory.c in Xen 3.2.x through 4.6.x does not properly hand back pages to a domain, which might allow guest OS administrators to cause a denial of service (host crash) via unspecified vectors related to domain teardown.

The eepro100 emulator in QEMU qemu-kvm blank allows local guest users to cause a denial of service (application crash and infinite loop) via vectors involving the command block list.

Stack-based buffer overflow in the megasas_ctrl_get_info function in QEMU, when built with SCSI MegaRAID SAS HBA emulation support, allows local guest users to cause a denial of service (QEMU instance crash) via a crafted SCSI controller CTRL_GET_INFO command.

The PCI backend driver in Xen, when running on an x86 system and using Linux 3.1.x through 4.3.x as the driver domain, allows local guest administrators to hit BUG conditions and cause a denial of service (NULL pointer dereference and host OS crash) by leveraging a system with access to a passed-through MSI or MSI-X capable physical PCI device and a crafted sequence of XEN_PCI_OP_* operations, aka "Linux pciback missing sanity checks."

Xen 4.4.x and earlier, when using a large number of VCPUs, does not properly handle read and write locks, which allows local x86 guest users to cause a denial of service (write denial or NMI watchdog timeout and host crash) via a large number of read requests, a different vulnerability than CVE-2014-9065.

The compatibility mode hypercall argument translation in Xen 3.3.x through 4.4.x, when running on a 64-bit hypervisor, allows local 32-bit HVM guests to cause a denial of service (host crash) via vectors involving altering the high halves of registers while in 64-bit mode.

Certain MMU virtualization operations in Xen 4.2.x through 4.4.x before the xsa97-hap patch, when using Hardware Assisted Paging (HAP), are not preemptible, which allows local HVM guest to cause a denial of service (vcpu consumption) by invoking these operations, which process every page assigned to a guest, a different vulnerability than CVE-2014-5149.

Certain MMU virtualization operations in Xen 4.2.x through 4.4.x, when using shadow pagetables, are not preemptible, which allows local HVM guest to cause a denial of service (vcpu consumption) by invoking these operations, which process every page assigned to a guest, a different vulnerability than CVE-2014-5146.

arch/x86/kvm/vmx.c in the KVM subsystem in the Linux kernel through 3.17.2 does not have an exit handler for the INVVPID instruction, which allows guest OS users to cause a denial of service (guest OS crash) via a crafted application.

Race condition in the __kvm_migrate_pit_timer function in arch/x86/kvm/i8254.c in the KVM subsystem in the Linux kernel through 3.17.2 allows guest OS users to cause a denial of service (host OS crash) by leveraging incorrect PIT emulation.