CVE-2025-21913
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk9th percentile - higher than 9% of all known CVEs
Summary
In the Linux kernel, a vulnerability in the amd_get_mmconfig_range() function for x86 has been fixed. Xen does not offer MSR_FAM10H_MMIO_CONF_BASE to all guests, causing an unchecked MSR access warning. The fix uses rdmsr_safe() instead of rdmsr() to safely handle the missing access.
Risk Assessment
The risk involves warning messages and potential system disruption during PNP0c01 device initialization in Xen virtualized environments. This may lead to incorrect MMCFG configuration detection and issues with PCI configuration space management.
Recommendation
Immediately update the Linux kernel to a version containing this fix. For systems using Xen, apply the patch that changes rdmsr() to rdmsr_safe() in the amd_get_mmconfig_range() function.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: x86/amd_nb: Use rdmsr_safe() in amd_get_mmconfig_range() Xen doesn't offer MSR_FAM10H_MMIO_CONF_BASE to all guests. This results in the following warning: unchecked MSR access error: RDMSR from 0xc0010058 at rIP: 0xffffffff8101d19f (xen_do_read_msr+0x7f/0xa0) Call Trace: xen_read_msr+0x1e/0x30 amd_get_mmconfig_range+0x2b/0x80 quirk_amd_mmconfig_area+0x28/0x100 pnp_fixup_device+0x39/0x50 __pnp_add_device+0xf/0x150 pnp_add_device+0x3d/0x100 pnpacpi_add_device_handler+0x1f9/0x280 acpi_ns_get_device_callback+0x104/0x1c0 acpi_ns_walk_namespace+0x1d0/0x260 acpi_get_devices+0x8a/0xb0 pnpacpi_init+0x50/0x80 do_one_initcall+0x46/0x2e0 kernel_init_freeable+0x1da/0x2f0 kernel_init+0x16/0x1b0 ret_from_fork+0x30/0x50 ret_from_fork_asm+0x1b/0x30 based on quirks for a "PNP0c01" device. Treating MMCFG as disabled is the right course of action, so no change is needed there. This was most likely exposed by fixing the Xen MSR accessors to not be silently-safe.