CVE-2026-72174
In the Linux kernel, the following vulnerability has been resolved:
fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
A PAGEMAP_SCAN ioctl requesting PM_SCAN_WP_MATCHING on a hugetlb VMA hangs the calling thread, unkillably, as soon as the scan reaches an unpopulated part of the range:
walk_hugetlb_range() holds the hugetlb vma lock for read across the whole walk. A present entry goes to ->hugetlb_entry(); an unpopulated one goes to ->pte_hole(), i.e. pagemap_scan_pte_hole(). To write-protect the hole that handler calls uffd_wp_range(), which on a hugetlb VMA reaches hugetlb_change_protection() and takes the same vma lock for write. The thread then blocks in down_write() waiting for the read lock it is itself holding.
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The populated path avoids this: pagemap_scan_hugetlb_entry() write-protects the entry inline under the page-table lock and never enters hugetlb_change_protection().
Do the same for holes. Fault in the page table and install the uffd-wp marker directly with make_uffd_wp_huge_pte() under the page-table lock, rather than routing through uffd_wp_range(). That is the same sequence hugetlb_change_protection() runs for an unpopulated entry, minus the vma write lock -- which is safe to skip because PMD sharing is disabled on uffd-wp VMAs (hugetlb_unshare_all_pmds() runs at registration), leaving nothing for that lock to serialise against.
Detalles técnicos trazas, registros y código del informe original
do_pagemap_scan()
walk_page_range()
walk_hugetlb_range()
hugetlb_vma_lock_read() # take the vma lock for read ...
pagemap_scan_pte_hole() # ... ->pte_hole() for a hole
uffd_wp_range()
change_protection()
hugetlb_change_protection()
hugetlb_vma_lock_write() # ... and block taking it for writeCVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-72174",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "52526ca7fdb905a768a93f8faa418e9b988fc34b",
"lessThan": "a6ac03652d9edc30c2912037ac83beb42cc67f8e",
"versionType": "git"
},
{
"status": "affected",
"version": "52526ca7fdb905a768a93f8faa418e9b988fc34b",
"lessThan": "43b987ed35be9be21a303d1036d4241fec9943df",
"versionType": "git"
},
{
"status": "affected",
"version": "52526ca7fdb905a768a93f8faa418e9b988fc34b",
"lessThan": "18b8a9700610299819d21fd0ea85d24726d17f65",
"versionType": "git"
},
{
"status": "affected",
"version": "52526ca7fdb905a768a93f8faa418e9b988fc34b",
"lessThan": "e92d92bbafb264dc0518d52b846a3c07ed8d523f",
"versionType": "git"
}
],
"programFiles": [
"fs/proc/task_mmu.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/proc/task_mmu.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-15T06:21:35.567",
"references": [
{
"url": "https://git.kernel.org/stable/c/18b8a9700610299819d21fd0ea85d24726d17f65",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/43b987ed35be9be21a303d1036d4241fec9943df",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/a6ac03652d9edc30c2912037ac83beb42cc67f8e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e92d92bbafb264dc0518d52b846a3c07ed8d523f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()\n\nA PAGEMAP_SCAN ioctl requesting PM_SCAN_WP_MATCHING on a hugetlb VMA hangs\nthe calling thread, unkillably, as soon as the scan reaches an unpopulated\npart of the range:\n\n do_pagemap_scan()\n walk_page_range()\n walk_hugetlb_range()\n hugetlb_vma_lock_read() # take the vma lock for read ...\n pagemap_scan_pte_hole() # ... ->pte_hole() for a hole\n uffd_wp_range()\n change_protection()\n hugetlb_change_protection()\n hugetlb_vma_lock_write() # ... and block taking it for write\n\nwalk_hugetlb_range() holds the hugetlb vma lock for read across the whole\nwalk. A present entry goes to ->hugetlb_entry(); an unpopulated one goes\nto ->pte_hole(), i.e. pagemap_scan_pte_hole(). To write-protect the hole\nthat handler calls uffd_wp_range(), which on a hugetlb VMA reaches\nhugetlb_change_protection() and takes the same vma lock for write. The\nthread then blocks in down_write() waiting for the read lock it is itself\nholding.\n\nThe populated path avoids this: pagemap_scan_hugetlb_entry()\nwrite-protects the entry inline under the page-table lock and never enters\nhugetlb_change_protection().\n\nDo the same for holes. Fault in the page table and install the uffd-wp\nmarker directly with make_uffd_wp_huge_pte() under the page-table lock,\nrather than routing through uffd_wp_range(). That is the same sequence\nhugetlb_change_protection() runs for an unpopulated entry, minus the vma\nwrite lock -- which is safe to skip because PMD sharing is disabled on\nuffd-wp VMAs (hugetlb_unshare_all_pmds() runs at registration), leaving\nnothing for that lock to serialise against."
}
],
"lastModified": "2026-08-17T06:18:17.883",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}