FKIE_CVE-2026-74518
Vulnerability from fkie_nvd - Published: 2026-08-15 13:17 - Updated: 2026-08-19 17:21
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/hugetlb: fix list corruption in allocate_file_region_entries()
allocate_file_region_entries() tops up resv->region_cache with freshly
allocated file_region descriptors. The allocation uses GFP_KERNEL, so
resv->lock is dropped around it: the new entries are gathered on a
stack-local list head, allocated_regions, and spliced into
resv->region_cache once the lock is re-acquired.
The splice used list_splice(), which moves the entries but does not
re-initialize the source head, so allocated_regions is left pointing at an
entry that now lives on resv->region_cache. The top-up runs in a while
loop that re-checks the cache deficit after re-acquiring the lock. For a
shared mapping the resv_map is shared by every mapper of the hugetlbfs
inode, so a concurrent region_chg()/region_add()/region_del() on the same
resv_map can consume cache entries during the unlocked window and force a
second iteration. That iteration calls list_add() on the stale head and
corrupts the list; with CONFIG_DEBUG_LIST the __list_add_valid() check
trips:
list_add corruption. next->prev should be prev (ffffc900011ff7f8),
but was ffff88814c281460. (next=ffff88814c545640).
kernel BUG at lib/list_debug.c:31!
allocate_file_region_entries+0x191/0x420
region_chg+0x267/0x300
hugetlb_reserve_pages+0x387/0xc80
hugetlbfs_file_mmap+0x2ce/0x3f0
mmap_region+0x1348/0x1a80
do_mmap+0x85e/0xb90
vm_mmap_pgoff+0x18c/0x330
ksys_mmap_pgoff+0x2a1/0x3e0
do_syscall_64+0xd7/0x420
Without CONFIG_DEBUG_LIST the bad list_add() silently links a kernel-stack
address into resv->region_cache, leading to later use-after-free.
This was observed as a real host panic on a dense KVM host where a QEMU
guest-RAM hugetlbfs file was mapped MAP_SHARED by both QEMU and a separate
SPDK/DPDK vhost-user target, generating concurrent region_* traffic on one
shared resv_map.
Use list_splice_init() so the source head is re-initialized empty after
each splice, making the retry loop safe.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/hugetlb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "01b8569233e47693d6ff7efa96d9854c55f936fc",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "9c5fdffc5e1ce84403c58289ee72697051803bf7",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "f3e54f6a5e1681f83d13e8716bc92ef5ecf121d3",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "62e1c2741a4d923d9854efd5927a6212aad7a187",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "587a0accc2b4fccc5cf7baf0fe34e50efde51f9c",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "126a70bf1a08ddc9d79c471ebdaa2b08cfbab8df",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "ac1bb7fd45088d0db57a22ce7729f258ebd63cf5",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
},
{
"lessThan": "dd9623f58ec702a07b2d67179d6fcea79c52231a",
"status": "affected",
"version": "d3ec7b6e09e512ba902b86bcca2c512fb06d492f",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"mm/hugetlb.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.10"
},
{
"lessThan": "5.10",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix list corruption in allocate_file_region_entries()\n\nallocate_file_region_entries() tops up resv-\u003eregion_cache with freshly\nallocated file_region descriptors. The allocation uses GFP_KERNEL, so\nresv-\u003elock is dropped around it: the new entries are gathered on a\nstack-local list head, allocated_regions, and spliced into\nresv-\u003eregion_cache once the lock is re-acquired.\n\nThe splice used list_splice(), which moves the entries but does not\nre-initialize the source head, so allocated_regions is left pointing at an\nentry that now lives on resv-\u003eregion_cache. The top-up runs in a while\nloop that re-checks the cache deficit after re-acquiring the lock. For a\nshared mapping the resv_map is shared by every mapper of the hugetlbfs\ninode, so a concurrent region_chg()/region_add()/region_del() on the same\nresv_map can consume cache entries during the unlocked window and force a\nsecond iteration. That iteration calls list_add() on the stale head and\ncorrupts the list; with CONFIG_DEBUG_LIST the __list_add_valid() check\ntrips:\n\n list_add corruption. next-\u003eprev should be prev (ffffc900011ff7f8),\n but was ffff88814c281460. (next=ffff88814c545640).\n kernel BUG at lib/list_debug.c:31!\n allocate_file_region_entries+0x191/0x420\n region_chg+0x267/0x300\n hugetlb_reserve_pages+0x387/0xc80\n hugetlbfs_file_mmap+0x2ce/0x3f0\n mmap_region+0x1348/0x1a80\n do_mmap+0x85e/0xb90\n vm_mmap_pgoff+0x18c/0x330\n ksys_mmap_pgoff+0x2a1/0x3e0\n do_syscall_64+0xd7/0x420\n\nWithout CONFIG_DEBUG_LIST the bad list_add() silently links a kernel-stack\naddress into resv-\u003eregion_cache, leading to later use-after-free.\n\nThis was observed as a real host panic on a dense KVM host where a QEMU\nguest-RAM hugetlbfs file was mapped MAP_SHARED by both QEMU and a separate\nSPDK/DPDK vhost-user target, generating concurrent region_* traffic on one\nshared resv_map.\n\nUse list_splice_init() so the source head is re-initialized empty after\neach splice, making the retry loop safe."
}
],
"id": "CVE-2026-74518",
"lastModified": "2026-08-19T17:21:08.543",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-15T13:17:56.967",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/01b8569233e47693d6ff7efa96d9854c55f936fc"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/126a70bf1a08ddc9d79c471ebdaa2b08cfbab8df"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/587a0accc2b4fccc5cf7baf0fe34e50efde51f9c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/62e1c2741a4d923d9854efd5927a6212aad7a187"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9c5fdffc5e1ce84403c58289ee72697051803bf7"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ac1bb7fd45088d0db57a22ce7729f258ebd63cf5"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/dd9623f58ec702a07b2d67179d6fcea79c52231a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f3e54f6a5e1681f83d13e8716bc92ef5ecf121d3"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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