CVE-2025-58142: 
Linux Debian vulnerability analysis and mitigation

CVE-2025-58142 is one of multiple vulnerabilities discovered in the Viridian interface of Xen hypervisor. This specific vulnerability involves a NULL pointer dereference that occurs when assuming the SIM page is mapped during the delivery of a synthetic timer message. The vulnerability was publicly disclosed on September 9, 2025, affecting Xen versions 4.13 and newer, specifically impacting x86 HVM guests with reference_tsc or stimer viridian extensions enabled (Xen Advisory).

The vulnerability is part of a series of issues related to the handling and accessing of guest memory pages in the viridian code. Specifically, CVE-2025-58142 manifests as a NULL pointer dereference that occurs when the system assumes the SIM page is mapped during the process of delivering a synthetic timer message. This vulnerability was documented as part of XSA-472 version 2, alongside other related vulnerabilities affecting the same component (Xen Advisory).

The exploitation of this vulnerability can lead to multiple severe consequences including Denial of Service (DoS) affecting the entire host, potential information leaks, or elevation of privilege. The impact is particularly significant for systems running vulnerable versions of Xen with specific extensions enabled (Xen Advisory).

Two primary mitigation strategies have been identified: 1) Disabling the reference_tsc and stimer viridian extensions will prevent the exploitation of this vulnerability, and 2) Applying the appropriate set of patches provided in the security advisory (xsa472-1.patch, xsa472-2.patch, xsa472-3.patch). System administrators are encouraged to update to the tip of the stable branch before applying these patches (Xen Advisory).