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
mdeslaurhypervisor packages are in universe. For
issues in the hypervisor, add appropriate
tags to each section, ex:
Tags_xen: universe-binary
Source: xen (LP Ubuntu Debian)
Ubuntu 12.04 ESM (Precise Pangolin):DNE
Ubuntu 14.04 ESM (Trusty Tahr):DNE
Ubuntu 16.04 LTS (Xenial Xerus):needs-triage
Ubuntu 18.04 LTS (Bionic Beaver):needs-triage
Ubuntu 19.10 (Eoan Ermine):needs-triage
Ubuntu 20.04 (Focal Fossa):not-affected (4.11.3+24-g14b62ab3e5-1ubuntu1)
Binaries built from this source package are in universe and so are supported by the community. For more details see
More Information

Updated: 2020-02-18 14:14:32 UTC (commit c0d61ad7c8b86ba29097cf5accfef1795e5a2080)