Xen Arm Page Reference Counting Vulnerability Leading to Hypervisor Crash

A vulnerability in Xen hypervisor on Arm systems, present in versions 4.12 and later, has been identified. This issue arises from improper handling of page references between domains, which can lead to a NULL pointer dereference in release builds. As a result, an unprivileged guest could cause a hypervisor crash, creating a denial-of-service condition for the entire host. While privilege escalation and information leaks cannot be ruled out, x86 systems are not affected.

Impact

Exploitation of this vulnerability can cause a hypervisor crash, leading to a denial-of-service condition on the host. However, privilege escalation and information leaks cannot be ruled out.

Remediation

Applying the patches available in the Xen Security Advisory XSA-473 resolves this vulnerability. Instructions for applying these patches can be found in the advisory.