CVE-2026-74716

Technical Description

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

accel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()

In amdxdna_insert_pages(), vm_flags_mod() sets VM_MIXEDMAP and clears

VM_PFNMAP. If an unprivileged userspace process mmaps a non-imported GEM

object and then calls madvise(MADV_DONTNEED), the PTEs will be

successfully cleared because VM_MIXEDMAP allows this (unlike VM_PFNMAP).

When userspace subsequently accesses the memory, drm_gem_shmem_fault()

handles the page fault and attempts to map the backing shmem page via

vmf_insert_pfn() which calls vmf_insert_pfn_prot(). Because the backing

shmem page is normal system memory (pfn_valid(pfn) is true) and the VMA

now has VM_MIXEDMAP set, won't this predictably trigger the explicit

assertion BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn))

Fix by removing the vm_flags_mod() call and replacing the vm_insert_pages()

pre-population with the handle_mm_fault() loop that was already used for

the impo

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