CVE-2026-43348

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER

When registering VTL0 memory via MSHV_ADD_VTL0_MEMORY, the kernel

computes pgmap->vmemmap_shift as the number of trailing zeros in the

OR of start_pfn and last_pfn, intending to use the largest compound

page order both endpoints are aligned to.

However, this value is not clamped to MAX_FOLIO_ORDER, so a

sufficiently aligned range (e.g. physical range

[0x800000000000, 0x800080000000), corresponding to start_pfn=0x800000000

with 35 trailing zeros) can produce a shift larger than what

memremap_pages() accepts, triggering a WARN and returning -EINVAL:

WARNING: ... memremap_pages+0x512/0x650

requested folio size unsupported

The MAX_FOLIO_ORDER check was added by

commit 646b67d57589 ("mm/memremap: reject unreasonable folio/compound

page sizes in memremap_pages()").

Fix this by clamping vmemmap_shift to MAX_FOLIO_ORDER so we always

request the largest order the k

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References