CVE-2026-74599 (GCVE-0-2026-74599)
Vulnerability from cvelistv5
Published
2026-08-22 15:31
Modified
2026-08-23 12:47
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/ptdump: always stabilise against page table freeing using init_mm
Previous commits have established the invariant that kernel page table
freeing is performed while an mmap read lock on init_mm is held, which
fixes races between ptdump and kernel page table freeing over init_mm.
However, x86 and arm64 can perform a ptdump over an mm other than init_mm
via ptdump_walk_pgd() and since kernel memory ranges are shared across
non-kernel mm's, this means that the race still exists for these cases.
Fix this by acquiring a nested mmap write lock for init_mm in
ptdump_walk_pgd().
This is safe as we take this after mmap write locking the mm, and nothing
acquires the init_mm lock first before locking an arbitrary mm, so no
deadlock is possible.
Also update walk_page_range_debug() to assert that init_mm is write
locked, add a comment explaining why and remove some redundant code, and
eliminate the unnecessary and confusing invocation of
walk_kernel_page_table_range().
We can safely remove the non-NULL check for walk.mm, as the mmap lock
asserts would NULL pointer deref if it was (and of course no callers do
this).
The first point at which ptdump can race kernel page table freeing is
commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page
table"), so we target this in the Fixes tag.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: b6bdb7517c3d3f41f20e5c2948d6bc3f8897394e Version: 31895cfd79564111cdd5a9f48c5d491ae26a238e Version: 9c7f7bdb1932f8c1e5f80d32c717184701afe701 Version: acdb4981644c8e31ccee294bdefff475c0cf587b Version: 0454e2fad9306961540ee7e84da47a8e345b7d22 Version: 4.4.125 ≤ Version: 4.9.91 ≤ Version: 4.14.31 ≤ Version: 4.15.14 ≤ |
||
{
"containers": {
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{
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"product": "Linux",
"programFiles": [
"mm/pagewalk.c",
"mm/ptdump.c"
],
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},
{
"lessThan": "4.5",
"status": "affected",
"version": "4.4.125",
"versionType": "semver"
},
{
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"status": "affected",
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{
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},
{
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}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"mm/pagewalk.c",
"mm/ptdump.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"version": "4.16"
},
{
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"version": "0",
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},
{
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"version": "5.10.266",
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},
{
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},
{
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},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
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},
{
"lessThanOrEqual": "6.18.*",
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"version": "6.18.45",
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},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
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},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
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{
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{
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],
"negate": false,
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/ptdump: always stabilise against page table freeing using init_mm\n\nPrevious commits have established the invariant that kernel page table\nfreeing is performed while an mmap read lock on init_mm is held, which\nfixes races between ptdump and kernel page table freeing over init_mm.\n\nHowever, x86 and arm64 can perform a ptdump over an mm other than init_mm\nvia ptdump_walk_pgd() and since kernel memory ranges are shared across\nnon-kernel mm\u0027s, this means that the race still exists for these cases.\n\nFix this by acquiring a nested mmap write lock for init_mm in\nptdump_walk_pgd().\n\nThis is safe as we take this after mmap write locking the mm, and nothing\nacquires the init_mm lock first before locking an arbitrary mm, so no\ndeadlock is possible.\n\nAlso update walk_page_range_debug() to assert that init_mm is write\nlocked, add a comment explaining why and remove some redundant code, and\neliminate the unnecessary and confusing invocation of\nwalk_kernel_page_table_range().\n\nWe can safely remove the non-NULL check for walk.mm, as the mmap lock\nasserts would NULL pointer deref if it was (and of course no callers do\nthis).\n\nThe first point at which ptdump can race kernel page table freeing is\ncommit b6bdb7517c3d (\"mm/vmalloc: add interfaces to free unmapped page\ntable\"), so we target this in the Fixes tag."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-23T12:47:39.758Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3c0391b9a774cc0854f3152e484a9d4835b12b40"
},
{
"url": "https://git.kernel.org/stable/c/cbd9583bb6f70733d0022a66d3546a15c76ae744"
},
{
"url": "https://git.kernel.org/stable/c/76df4edf7d61ecb711bc517ff4c20a5e85c4e9f7"
},
{
"url": "https://git.kernel.org/stable/c/b9c6d048bdfaae78d7d921b454f7de7baefaa2f0"
},
{
"url": "https://git.kernel.org/stable/c/7f740664aec1f832953c2e6d9b8920cd6c8bcc0c"
},
{
"url": "https://git.kernel.org/stable/c/4adc4c9a9a43d61fe476dfe10811f3df2e7e4106"
},
{
"url": "https://git.kernel.org/stable/c/27c32e5538344b13c1505a08861e04620c125d47"
}
],
"title": "mm/ptdump: always stabilise against page table freeing using init_mm",
"x_generator": {
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}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74599",
"datePublished": "2026-08-22T15:31:48.604Z",
"dateReserved": "2026-08-15T05:44:03.919Z",
"dateUpdated": "2026-08-23T12:47:39.758Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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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.
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