CVE-2026-80719
In the Linux kernel, the following vulnerability has been resolved:
mm: mglru: fix stale batch updates after memcg reparenting
The mglru page table walker batches per-generation size deltas in walk->nr_pages while walking page tables without holding the lruvec lock. The reset_batch_size() later folds those deltas into walk->lruvec under the lruvec lock.
The page table walker can run concurrently with the memcg reparenting path as follows:
CPU0 CPU1 ==== ====
This will trigger the following warning in lru_gen_exit_memcg():
And the user-visible impact of underestimated nr_pages in MGLRU was premature OOMs because MGLRU does not try to reclaim memory when nr_pages reaches zero, but there are still more pages.
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To fix it, make reset_batch_size() check CSS_DYING under RCU before flushing the pending batch. A non-dying memcg keeps the original lruvec stable against RCU-delayed offlining; a dying memcg redirects the deltas to the first non-dying ancestor.
Detalles técnicos trazas, registros y código del informe original
walk_mm
--> walk_page_range
--> update_batch_size
--> walk->nr_pages += delta
mem_cgroup_css_offline
--> memcg_reparent_objcgs
--> lock lruvec
lru_gen_reparent_memcg
--> reparent child folios to parent
unlock lruvec
lock lruvec
reset_batch_size
--> child lrugen->nr_pages += delta
VM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0,
sizeof(lruvec->lrugen.nr_pages)));CVSS
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: 0.20%
- Percentil entre todas las CVEs puntuadas: 9
- Fecha de la puntuación: 6/10/2026
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-2026-80719",
"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": "f304652609eae3814b0e9d11c75c0e0cb62da31f",
"lessThan": "fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101",
"versionType": "git"
},
{
"status": "affected",
"version": "f304652609eae3814b0e9d11c75c0e0cb62da31f",
"lessThan": "de4660898b7aa7e03d3b120a6bfa6b26211e4e77",
"versionType": "git"
}
],
"programFiles": [
"include/linux/memcontrol.h",
"mm/vmscan.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "7.1"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "7.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/linux/memcontrol.h",
"mm/vmscan.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-08-28T08:16:57.720",
"references": [
{
"url": "https://git.kernel.org/stable/c/de4660898b7aa7e03d3b120a6bfa6b26211e4e77",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/fceb6b7f3ddec6ea9fc11577f4cf1b2da73a3101",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: mglru: fix stale batch updates after memcg reparenting\n\nThe mglru page table walker batches per-generation size deltas in\nwalk->nr_pages while walking page tables without holding the lruvec lock. \nThe reset_batch_size() later folds those deltas into walk->lruvec under\nthe lruvec lock.\n\nThe page table walker can run concurrently with the memcg reparenting path\nas follows:\n\nCPU0 CPU1\n==== ====\n\nwalk_mm\n--> walk_page_range\n --> update_batch_size\n --> walk->nr_pages += delta\n\n mem_cgroup_css_offline\n --> memcg_reparent_objcgs\n --> lock lruvec\n lru_gen_reparent_memcg\n --> reparent child folios to parent\n unlock lruvec\n\n lock lruvec\n reset_batch_size\n --> child lrugen->nr_pages += delta\n\nThis will trigger the following warning in lru_gen_exit_memcg():\n\n\tVM_WARN_ON_ONCE(memchr_inv(lruvec->lrugen.nr_pages, 0,\n\t\t\t\t sizeof(lruvec->lrugen.nr_pages)));\n\nAnd the user-visible impact of underestimated nr_pages in MGLRU was\npremature OOMs because MGLRU does not try to reclaim memory when nr_pages\nreaches zero, but there are still more pages.\n\nTo fix it, make reset_batch_size() check CSS_DYING under RCU before\nflushing the pending batch. A non-dying memcg keeps the original lruvec\nstable against RCU-delayed offlining; a dying memcg redirects the deltas\nto the first non-dying ancestor."
}
],
"lastModified": "2026-08-28T08:16:57.720",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}