GHSA-44JX-474F-M2QV
Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-22 18:30In 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.
{
"affected": [],
"aliases": [
"CVE-2026-74716"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-22T16:16:46Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\naccel/amdxdna: Fix locally exploitable BUG_ON in amdxdna_insert_pages()\n\nIn amdxdna_insert_pages(), vm_flags_mod() sets VM_MIXEDMAP and clears\nVM_PFNMAP. If an unprivileged userspace process mmaps a non-imported GEM\nobject and then calls madvise(MADV_DONTNEED), the PTEs will be\nsuccessfully cleared because VM_MIXEDMAP allows this (unlike VM_PFNMAP).\n\nWhen userspace subsequently accesses the memory, drm_gem_shmem_fault()\nhandles the page fault and attempts to map the backing shmem page via\nvmf_insert_pfn() which calls vmf_insert_pfn_prot(). Because the backing\nshmem page is normal system memory (pfn_valid(pfn) is true) and the VMA\nnow has VM_MIXEDMAP set, won\u0027t this predictably trigger the explicit\nassertion BUG_ON((vma-\u003evm_flags \u0026 VM_MIXEDMAP) \u0026\u0026 pfn_valid(pfn))\n\nFix by removing the vm_flags_mod() call and replacing the vm_insert_pages()\npre-population with the handle_mm_fault() loop that was already used for\nthe import (dma-buf) path.",
"id": "GHSA-44jx-474f-m2qv",
"modified": "2026-08-22T18:30:30Z",
"published": "2026-08-22T18:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74716"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/13339132d89d00b513dff0730bff3a313b9b13b5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4a19f7ab5972ef608b31ae921419bc3e04b3f8ad"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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