Xen 3.x, possibly before 3.1.2, when running on IA64 systems, does not check the RID value for movtorr, which allows a VTi domain to read memory of other domains.

Xen 3.1.1 allows virtual guest system users to cause a denial of service (hypervisor crash) by using a debug register (DR7) to set certain breakpoints.

Xen 3.1.1 does not prevent modification of the CR4 TSC from applications, which allows pv guests to cause a denial of service (crash).

pygrub (tools/pygrub/src/GrubConf.py) in Xen 3.0.3, when booting a guest domain, allows local users with elevated privileges in the guest domain to execute arbitrary commands in domain 0 via a crafted grub.conf file whose contents are used in exec statements.

(1) xenbaked and (2) xenmon.py in Xen 3.1 and earlier allow local users to truncate arbitrary files via a symlink attack on /tmp/xenq-shm.

The ssmi emulation in Xen 5.1 on IA64 architectures allows attackers to cause a denial of service (dom0 panic) via certain traffic, as demonstrated using an FTP stress test tool.