CVE-2026-98225 (GCVE-0-2026-98225)
Vulnerability from cvelistv5
Published
2026-10-06 08:45
Modified
2026-10-19 09:15
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
mm/shrinker: fix bogus set_shrinker_bit() with cgroup.memory=nokmem
With cgroup.memory=nokmem, shrinker_memcg_alloc() bails out early and
never allocates an id, so shrinker->id keeps the 0 it got from the
kzalloc() in shrinker_alloc(). __list_lru_init() then copies that 0 into
lru->shrinker_id, where it looks like a valid bit index.
Nothing calls expand_shrinker_info() on nokmem either, so shrinker_nr_max
stays 0 and every memcg ends up with an empty map (map_nr_max == 0).
deferred_split_folio() hands a real memcg to __list_lru_add() regardless
of whether the lru is memcg aware, so the first THP queued in a cgroup
does set_shrinker_bit(memcg, nid, 0) and trips the bounds check:
WARNING: mm/shrinker.c:212 at set_shrinker_bit+0x7d/0x90, CPU#126
Call Trace:
<TASK>
deferred_split_folio+0x18c/0x220
map_anon_folio_pmd_nopf+0xdd/0x130
map_anon_folio_pmd_pf+0x14/0xb0
do_huge_pmd_anonymous_page+0x1a1/0x620
__handle_mm_fault+0xea9/0x10d0
handle_mm_fault+0xe5/0x320
do_user_addr_fault+0x1cc/0x870
exc_page_fault+0x81/0x1b0
asm_exc_page_fault+0x27/0x30
</TASK>
Harmless, the WARN_ON_ONCE() is what keeps the out of bounds unit[] read
from happening, but the id should not look valid in the first place.
Clear it before returning.
Two other spots could paper over this: drop the id in __list_lru_init()
when nokmem turns memcg_aware off, or make deferred_split_folio() pass
NULL like list_lru_add_obj() does. Both leave shrinker->id lying around
for the next caller, so fix it where the id is handed out.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"mm/shrinker.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "469c12a69ab1842a9090b6c074ffedbfd9584f9c",
"status": "affected",
"version": "fafaeceb89a5e2e856ff04c2cacb6cae4a2ecb67",
"versionType": "git"
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{
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"status": "affected",
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"versionType": "git"
}
]
},
{
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"product": "Linux",
"programFiles": [
"mm/shrinker.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.2"
},
{
"lessThan": "7.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.8",
"versionStartIncluding": "7.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "7.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/shrinker: fix bogus set_shrinker_bit() with cgroup.memory=nokmem\n\nWith cgroup.memory=nokmem, shrinker_memcg_alloc() bails out early and\nnever allocates an id, so shrinker-\u003eid keeps the 0 it got from the\nkzalloc() in shrinker_alloc(). __list_lru_init() then copies that 0 into\nlru-\u003eshrinker_id, where it looks like a valid bit index.\n\nNothing calls expand_shrinker_info() on nokmem either, so shrinker_nr_max\nstays 0 and every memcg ends up with an empty map (map_nr_max == 0).\n\ndeferred_split_folio() hands a real memcg to __list_lru_add() regardless\nof whether the lru is memcg aware, so the first THP queued in a cgroup\ndoes set_shrinker_bit(memcg, nid, 0) and trips the bounds check:\n\nWARNING: mm/shrinker.c:212 at set_shrinker_bit+0x7d/0x90, CPU#126\nCall Trace:\n \u003cTASK\u003e\n deferred_split_folio+0x18c/0x220\n map_anon_folio_pmd_nopf+0xdd/0x130\n map_anon_folio_pmd_pf+0x14/0xb0\n do_huge_pmd_anonymous_page+0x1a1/0x620\n __handle_mm_fault+0xea9/0x10d0\n handle_mm_fault+0xe5/0x320\n do_user_addr_fault+0x1cc/0x870\n exc_page_fault+0x81/0x1b0\n asm_exc_page_fault+0x27/0x30\n \u003c/TASK\u003e\n\nHarmless, the WARN_ON_ONCE() is what keeps the out of bounds unit[] read\nfrom happening, but the id should not look valid in the first place. \nClear it before returning.\n\nTwo other spots could paper over this: drop the id in __list_lru_init()\nwhen nokmem turns memcg_aware off, or make deferred_split_folio() pass\nNULL like list_lru_add_obj() does. Both leave shrinker-\u003eid lying around\nfor the next caller, so fix it where the id is handed out."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T09:15:57.057Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/469c12a69ab1842a9090b6c074ffedbfd9584f9c"
},
{
"url": "https://git.kernel.org/stable/c/932cfb25e7ce98d1f93895671ec186a3087e4f80"
}
],
"title": "mm/shrinker: fix bogus set_shrinker_bit() with cgroup.memory=nokmem",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98225",
"datePublished": "2026-10-06T08:45:00.458Z",
"dateReserved": "2026-09-25T10:25:14.327Z",
"dateUpdated": "2026-10-19T09:15:57.057Z",
"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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