CVE-2025-71114: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-71114 is a Linux kernel vulnerability in the VIA watchdog driver (via_wdt) that causes a critical boot hang due to an unnamed MMIO resource allocation. The driver uses allocate_resource() to reserve a memory-mapped I/O region for the watchdog control register but fails to assign a name to the allocated resource, resulting in a <BAD> entry in the kernel resource tree under /proc/iomem on x86 platforms. This defect was published on January 14, 2026, and affects Linux kernel versions from 3.3 through multiple stable branches up to 6.18.2. It carries a CVSS v3.1 base score of 5.5 (Medium) (Feedly, kernel.org patches).

The root cause is classified as CWE-401 (Missing Release of Memory after Effective Lifetime), reflecting improper resource lifecycle management in the via_wdt kernel driver. When allocate_resource() is called to reserve the MMIO region, the resulting resource struct is left without a .name field, causing the kernel's resource tree to record an invalid <BAD> entry in /proc/iomem. During subsequent boot-time resource lookups and conflict checks on x86 platforms, the kernel fails to handle this unnamed entry correctly, leading to a system hang. The vulnerability requires local access with low privileges to trigger (e.g., loading the via_wdt module), and no special configuration beyond having the VIA watchdog driver enabled is needed (Feedly).

The primary impact is a complete availability loss: affected systems running the VIA watchdog driver can hang during boot, rendering them entirely unresponsive and unable to complete startup. There is no confidentiality or integrity impact — the vulnerability is purely a denial-of-service condition affecting system availability. The scope is limited to systems with VIA hardware and the via_wdt driver loaded, primarily x86 platforms running affected kernel versions (Feedly).

Patches have been applied across multiple Linux kernel stable branches. Administrators should update to the following fixed versions or later: 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, or 6.18.3. Patches are available via the kernel.org stable repositories. As a temporary workaround for systems that cannot be updated immediately, disabling the VIA watchdog driver (blacklisting the via_wdt module) will prevent the vulnerable code path from executing. Systems running kernel versions prior to 3.3.1 are not affected (Feedly, kernel.org patches).