CVE-2023-54019
In the Linux kernel, the following vulnerability has been resolved:
sched/psi: use kernfs polling functions for PSI trigger polling
Destroying psi trigger in cgroup_file_release causes UAF issues when a cgroup is removed from under a polling process. This is happening because cgroup removal causes a call to cgroup_file_release while the actual file is still alive. Destroying the trigger at this point would also destroy its waitqueue head and if there is still a polling process on that file accessing the waitqueue, it will step on the freed pointer:
Patch [1] fixed this issue for epoll() case using wake_up_pollfree(), however the same issue exists for synchronous poll() case.
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The root cause of this issue is that the lifecycles of the psi trigger's waitqueue and of the file associated with the trigger are different. Fix this by using kernfs_generic_poll function when polling on cgroup-specific psi triggers. It internally uses kernfs_open_node->poll waitqueue head with its lifecycle tied to the file's lifecycle. This also renders the fix in [1] obsolete, so revert it.
[1] commit c2dbe32d5db5 ("sched/psi: Fix use-after-free in ep_remove_wait_queue()")
Detalles técnicos trazas, registros y código del informe original
do_select
vfs_poll
do_rmdir
cgroup_rmdir
kernfs_drain_open_files
cgroup_file_release
cgroup_pressure_release
psi_trigger_destroy
wake_up_pollfree(&t->event_wait)
// vfs_poll is unblocked
synchronize_rcu
kfree(t)
poll_freewait -> UAF access to the trigger's waitqueue headCVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.14%
- Percentil entre todas las CVEs puntuadas: 3
- 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).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1499.004Application or System Exploitationimpact75 %
Vulnerabilidad local de UAF en kernel que permite a un atacante con privilegios de usuario (PR:L) causar denegación de servicio (crash/panic) al explotar la liberación prematura de memoria en el subsistema PSI.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
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-2023-54019",
"cveTags": [],
"metrics": {
"cvssMetricV31": [
{
"type": "Secondary",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 1.8
}
]
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"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5",
"lessThan": "92cc0153324b6ae8577a39f5bf2cd83c9a34ea6a",
"versionType": "git"
},
{
"status": "affected",
"version": "0e94682b73bfa6c44c98af7a26771c9c08c055d5",
"lessThan": "d124ab17024cc85a1079b7810a018a497ebc13da",
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{
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"lessThan": "aff037078ecaecf34a7c2afab1341815f90fba5e",
"versionType": "git"
}
],
"programFiles": [
"include/linux/psi.h",
"include/linux/psi_types.h",
"kernel/cgroup/cgroup.c",
"kernel/sched/psi.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.42",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.4.7",
"versionType": "semver",
"lessThanOrEqual": "6.4.*"
},
{
"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/linux/psi.h",
"include/linux/psi_types.h",
"kernel/cgroup/cgroup.c",
"kernel/sched/psi.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2025-12-24T11:15:54.903",
"references": [
{
"url": "https://git.kernel.org/stable/c/92cc0153324b6ae8577a39f5bf2cd83c9a34ea6a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/aff037078ecaecf34a7c2afab1341815f90fba5e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/d124ab17024cc85a1079b7810a018a497ebc13da",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Deferred",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/psi: use kernfs polling functions for PSI trigger polling\n\nDestroying psi trigger in cgroup_file_release causes UAF issues when\na cgroup is removed from under a polling process. This is happening\nbecause cgroup removal causes a call to cgroup_file_release while the\nactual file is still alive. Destroying the trigger at this point would\nalso destroy its waitqueue head and if there is still a polling process\non that file accessing the waitqueue, it will step on the freed pointer:\n\ndo_select\n vfs_poll\n do_rmdir\n cgroup_rmdir\n kernfs_drain_open_files\n cgroup_file_release\n cgroup_pressure_release\n psi_trigger_destroy\n wake_up_pollfree(&t->event_wait)\n// vfs_poll is unblocked\n synchronize_rcu\n kfree(t)\n poll_freewait -> UAF access to the trigger's waitqueue head\n\nPatch [1] fixed this issue for epoll() case using wake_up_pollfree(),\nhowever the same issue exists for synchronous poll() case.\nThe root cause of this issue is that the lifecycles of the psi trigger's\nwaitqueue and of the file associated with the trigger are different. Fix\nthis by using kernfs_generic_poll function when polling on cgroup-specific\npsi triggers. It internally uses kernfs_open_node->poll waitqueue head\nwith its lifecycle tied to the file's lifecycle. This also renders the\nfix in [1] obsolete, so revert it.\n\n[1] commit c2dbe32d5db5 (\"sched/psi: Fix use-after-free in ep_remove_wait_queue()\")"
}
],
"lastModified": "2026-08-04T10:19:25.627",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}