An issue was discovered in Xen through 4.12.x allowing x86 guest OS users to cause a denial of service (infinite loop) because certain bit iteration is mishandled. In a number of places bitmaps are being used by the hypervisor to track certain state. Iteration over all bits involves functions which may misbehave in certain corner cases: On x86 accesses to bitmaps with a compile time known size of 64 may incur undefined behavior, which may in particular result in infinite loops. A malicious guest may cause a hypervisor crash or hang, resulting in a Denial of Service (DoS). All versions of Xen are vulnerable. x86 systems with 64 or more nodes are vulnerable (there might not be any such systems that Xen would run on). x86 systems with less than 64 nodes are not vulnerable.

An issue was discovered in Xen through 4.12.x allowing 32-bit Arm guest OS users to cause a denial of service (out-of-bounds access) because certain bit iteration is mishandled. In a number of places bitmaps are being used by the hypervisor to track certain state. Iteration over all bits involves functions which may misbehave in certain corner cases: On 32-bit Arm accesses to bitmaps with bit a count which is a multiple of 32, an out of bounds access may occur. A malicious guest may cause a hypervisor crash or hang, resulting in a Denial of Service (DoS). All versions of Xen are vulnerable. 32-bit Arm systems are vulnerable. 64-bit Arm systems are not vulnerable.

An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to gain host OS privileges by leveraging race conditions in pagetable promotion and demotion operations, because of an incomplete fix for CVE-2019-18421. XSA-299 addressed several critical issues in restartable PV type change operations. Despite extensive testing and auditing, some corner cases were missed. A malicious PV guest administrator may be able to escalate their privilege to that of the host. All security-supported versions of Xen are vulnerable. Only x86 systems are affected. Arm systems are not affected. Only x86 PV guests can leverage the vulnerability. x86 HVM and PVH guests cannot leverage the vulnerability. Note that these attacks require very precise timing, which may be difficult to exploit in practice.

An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device (and assignable-add is not used), because of an incomplete fix for CVE-2019-18424. XSA-302 relies on the use of libxl's "assignable-add" feature to prepare devices to be assigned to untrusted guests. Unfortunately, this is not considered a strictly required step for device assignment. The PCI passthrough documentation on the wiki describes alternate ways of preparing devices for assignment, and libvirt uses its own ways as well. Hosts where these "alternate" methods are used will still leave the system in a vulnerable state after the device comes back from a guest. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI pass-through) are vulnerable. Systems which do not...

An issue was discovered in Xen through 4.12.x allowing x86 PV guest OS users to cause a denial of service via degenerate chains of linear pagetables, because of an incorrect fix for CVE-2017-15595. "Linear pagetables" is a technique which involves either pointing a pagetable at itself, or to another pagetable of the same or higher level. Xen has limited support for linear pagetables: A page may either point to itself, or point to another pagetable of the same level (i.e., L2 to L2, L3 to L3, and so on). XSA-240 introduced an additional restriction that limited the "depth" of such chains by allowing pages to either *point to* other pages of the same level, or *be pointed to* by other pages of the same level, but not both. To implement this, we keep track of the number of outstanding times a page points to or is pointed to another page table, to prevent both from happening at the same time. Unfortunately, the original commit introducing this reset this count when resuming validation o...

An issue was discovered in Xen through 4.12.x allowing x86 AMD HVM guest OS users to cause a denial of service or possibly gain privileges by triggering data-structure access during pagetable-height updates. When running on AMD systems with an IOMMU, Xen attempted to dynamically adapt the number of levels of pagetables (the pagetable height) in the IOMMU according to the guest's address space size. The code to select and update the height had several bugs. Notably, the update was done without taking a lock which is necessary for safe operation. A malicious guest administrator can cause Xen to access data structures while they are being modified, causing Xen to crash. Privilege escalation is thought to be very difficult but cannot be ruled out. Additionally, there is a potential memory leak of 4kb per guest boot, under memory pressure. Only Xen on AMD CPUs is vulnerable. Xen running on Intel CPUs is not vulnerable. ARM systems are not vulnerable. Only systems where guests are given d...

read_textobject in read.c in Xfig fig2dev 3.2.7b has a stack-based buffer overflow because of an incorrect sscanf.

In Wireshark 3.0.0 to 3.0.6 and 2.6.0 to 2.6.12, the CMS dissector could crash. This was addressed in epan/dissectors/asn1/cms/packet-cms-template.c by ensuring that an object identifier is set to NULL after a ContentInfo dissection.

In the Linux kernel before 5.1.6, there is a use-after-free in serial_ir_init_module() in drivers/media/rc/serial_ir.c.

In the Linux kernel before 5.2.10, there is a race condition bug that can be caused by a malicious USB device in the USB character device driver layer, aka CID-303911cfc5b9. This affects drivers/usb/core/file.c.

In the Linux kernel before 5.2.9, there is an info-leak bug that can be caused by a malicious USB device in the drivers/net/can/usb/peak_usb/pcan_usb_pro.c driver, aka CID-ead16e53c2f0.

In the Linux kernel before 5.2.9, there is an info-leak bug that can be caused by a malicious USB device in the drivers/net/can/usb/peak_usb/pcan_usb_fd.c driver, aka CID-30a8beeb3042.

In the Linux kernel before 5.3.11, there is an info-leak bug that can be caused by a malicious USB device in the drivers/net/can/usb/peak_usb/pcan_usb_core.c driver, aka CID-f7a1337f0d29.

In the Linux kernel before 5.3.4, there is an info-leak bug that can be caused by a malicious USB device in the drivers/media/usb/ttusb-dec/ttusb_dec.c driver, aka CID-a10feaf8c464.

In the Linux kernel before 5.3.9, there are multiple out-of-bounds write bugs that can be caused by a malicious USB device in the Linux kernel HID drivers, aka CID-d9d4b1e46d95. This affects drivers/hid/hid-axff.c, drivers/hid/hid-dr.c, drivers/hid/hid-emsff.c, drivers/hid/hid-gaff.c, drivers/hid/hid-holtekff.c, drivers/hid/hid-lg2ff.c, drivers/hid/hid-lg3ff.c, drivers/hid/hid-lg4ff.c, drivers/hid/hid-lgff.c, drivers/hid/hid-logitech-hidpp.c, drivers/hid/hid-microsoft.c, drivers/hid/hid-sony.c, drivers/hid/hid-tmff.c, and drivers/hid/hid-zpff.c.

In the Linux kernel before 5.2.9, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/usb/misc/yurex.c driver, aka CID-fc05481b2fca.

In the Linux kernel before 5.2.10, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/usb/class/cdc-acm.c driver, aka CID-c52873e5a1ef.

In the Linux kernel before 5.3.11, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/net/can/usb/mcba_usb.c driver, aka CID-4d6636498c41.

In the Linux kernel before 5.3.7, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/usb/misc/iowarrior.c driver, aka CID-edc4746f253d.

In the Linux kernel before 5.2.10, there is a use-after-free bug that can be caused by a malicious USB device in the drivers/hid/usbhid/hiddev.c driver, aka CID-9c09b214f30e.