CVE-2023-34320: 
Linux Debian vulnerability analysis and mitigation

CVE-2023-34320 affects Cortex-A77 cores (r0p0 and r1p0) due to erratum 1508412, where software could experience a core deadlock under specific circumstances involving either a load to device or non-cacheable memory, and either a store exclusive or register read of the Physical Address Register (PAR_EL1) in close proximity (XEN Advisory).

The vulnerability has a CVSS v3.1 Base Score of 5.5 (MEDIUM) with vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. The issue is classified as CWE-667 (Improper Locking) and affects specific versions of ARM Cortex-A77 firmware (r0p0 and r1p0) (NVD).

A malicious guest that doesn't include the workaround for erratum 1508412 could trigger a deadlock on the core, which will ultimately result in a system-wide deadlock (XEN Advisory).

The vulnerability requires local access with low privilege and no user interaction. The attack complexity is considered low, making it relatively straightforward to exploit for an attacker with the necessary access (NVD).

To properly handle the erratum, it requires an updated firmware and both the hypervisor and guest OSes must have the workaround implemented. However, it is not possible to security support Xen on the Cortex-A77, even on systems with the workaround enabled. The only option is to run Xen with trusted guests only (XEN Advisory).