Executive brief
A vulnerability in the Linux kernel's VIA watchdog driver can cause systems to hang or freeze during the boot process. This occurs because the driver fails to properly name a memory resource, leading to internal errors when the system tries to manage its hardware. For businesses, this can result in unexpected downtime or the inability to restart critical servers and industrial controllers using affected hardware.
Technical details
A vulnerability in the via_wdt driver stems from the use of allocate_resource() to reserve an MMIO region for the watchdog control register without providing a resource name. On x86 platforms, this results in an entry marked as '<BAD>' in the kernel resource tree (visible via /proc/iomem). During the boot sequence, subsequent resource lookups and conflict checks fail to handle this invalid entry, triggering a critical system hang. The issue is resolved by explicitly assigning a name to the resource before allocation. Patches have been backported to multiple stable kernel branches.
Affected products
- Linux Linux Kernel versions prior to 6.13-rc1
- Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6 and later
Timeline
- 2025-09-28: other: Patch authored
- 2025-11-15: other: Patch committed to mainline
- 2026-01-14: advisory: NVD publication date
- 2026-07-14: advisory: Siemens advisory published
References
- https://git.kernel.org/stable/c/1d56025a3af50db0f3da2792f41eb9943eee5324
- https://git.kernel.org/stable/c/47c910965c936724070d2a8094a4c3ed8f452856
- https://git.kernel.org/stable/c/7aa31ee9ec92915926e74731378c009c9cc04928
- https://git.kernel.org/stable/c/c6a2dd4f2e4e6cbdfe7a1618160281af897b75db
- https://git.kernel.org/stable/c/c7b986adc9e9336066350542ac5a2005d305ae78
- https://git.kernel.org/stable/c/d2c7c90aca7b37f60f16b2bedcfeb16204f2f35d
- https://git.kernel.org/stable/c/f7b6370d0fbee06a867037d675797a606cb62e57