CVE-2019-19581

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.

Notes