CVE Catalog

CVE-2026-74716

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel amdxdna_insert_pages() function in the accel/amdxdna driver, there is a BUG_ON vulnerability. The vm_flags_mod() call sets VM_MIXEDMAP and clears VM_PFNMAP, allowing an unprivileged process to call madvise(MADV_DONTNEED) on a mapped GEM object, and subsequent memory access triggers BUG_ON in vmf_insert_pfn_prot() due to pfn_valid(pfn) and VM_MIXEDMAP.

Risk Assessment

The vulnerability can be exploited locally to trigger BUG_ON, leading to system crash (kernel panic) and DoS attacks by unprivileged users.

Recommendation

Apply the Linux kernel patch that removes the vm_flags_mod() call and replaces the vm_insert_pages() pre-population with the handle_mm_fault() loop used in the import path.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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 import (dma-buf) path.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS