CVE-2026-31575 (GCVE-0-2026-31575)
Vulnerability from cvelistv5
Published
2026-04-24 14:42
Modified
2026-04-27 13:56
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/userfaultfd: fix hugetlb fault mutex hash calculation
In mfill_atomic_hugetlb(), linear_page_index() is used to calculate the
page index for hugetlb_fault_mutex_hash(). However, linear_page_index()
returns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash()
expects the index in huge page units. This mismatch means that different
addresses within the same huge page can produce different hash values,
leading to the use of different mutexes for the same huge page. This can
cause races between faulting threads, which can corrupt the reservation
map and trigger the BUG_ON in resv_map_release().
Fix this by introducing hugetlb_linear_page_index(), which returns the
page index in huge page granularity, and using it in place of
linear_page_index().
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/linux/hugetlb.h",
"mm/userfaultfd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "5a525c43baaba0bf3063f86996ca3623b71e4172",
"status": "affected",
"version": "a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3",
"versionType": "git"
},
{
"lessThan": "574501ede47ac439afd67ba9812bc66722d500ba",
"status": "affected",
"version": "a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3",
"versionType": "git"
},
{
"lessThan": "08282b1bf74c69fc8ecd25493e7fdb5460f01290",
"status": "affected",
"version": "a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3",
"versionType": "git"
},
{
"lessThan": "f4689fc089765d36c026063fb22d23533e883eb6",
"status": "affected",
"version": "a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3",
"versionType": "git"
},
{
"lessThan": "0217c7fb4de4a40cee667eb21901f3204effe5ac",
"status": "affected",
"version": "a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/linux/hugetlb.h",
"mm/userfaultfd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.7"
},
{
"lessThan": "6.7",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.84",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.24",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.14",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.0.*",
"status": "unaffected",
"version": "7.0.1",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.1-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.84",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.24",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.14",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0.1",
"versionStartIncluding": "6.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1-rc1",
"versionStartIncluding": "6.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/userfaultfd: fix hugetlb fault mutex hash calculation\n\nIn mfill_atomic_hugetlb(), linear_page_index() is used to calculate the\npage index for hugetlb_fault_mutex_hash(). However, linear_page_index()\nreturns the index in PAGE_SIZE units, while hugetlb_fault_mutex_hash()\nexpects the index in huge page units. This mismatch means that different\naddresses within the same huge page can produce different hash values,\nleading to the use of different mutexes for the same huge page. This can\ncause races between faulting threads, which can corrupt the reservation\nmap and trigger the BUG_ON in resv_map_release().\n\nFix this by introducing hugetlb_linear_page_index(), which returns the\npage index in huge page granularity, and using it in place of\nlinear_page_index()."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-27T13:56:22.686Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/5a525c43baaba0bf3063f86996ca3623b71e4172"
},
{
"url": "https://git.kernel.org/stable/c/574501ede47ac439afd67ba9812bc66722d500ba"
},
{
"url": "https://git.kernel.org/stable/c/08282b1bf74c69fc8ecd25493e7fdb5460f01290"
},
{
"url": "https://git.kernel.org/stable/c/f4689fc089765d36c026063fb22d23533e883eb6"
},
{
"url": "https://git.kernel.org/stable/c/0217c7fb4de4a40cee667eb21901f3204effe5ac"
}
],
"title": "mm/userfaultfd: fix hugetlb fault mutex hash calculation",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-31575",
"datePublished": "2026-04-24T14:42:07.502Z",
"dateReserved": "2026-03-09T15:48:24.119Z",
"dateUpdated": "2026-04-27T13:56:22.686Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…