CVE-2026-97526
In the Linux kernel, the following vulnerability has been resolved:
s390/pai: Support CPU hotplug for PMU PAI
The command 'perf stat -e pai_crypto/CRYPTO_ALL/ -- <command>' crashes the kernel when CPUs are hotplug added during that run.
Root cause is the missing allocation of per-CPU data structures for that new CPU. The allocation is dynamic and the first event that has task context creates such a structure for each online CPU. This is not sufficient. CPUs may be offline during event creation and can be set online during the perf run time. For example commands
# echo 0 > /sys/devices/system/cpu/cpu1/online # perf stat -e cycles -i -- stress-ng -t10s --matrix X # sleep 1 # echo 1 > /sys/devices/system/cpu/cpu1/online
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Currently without a CPU hotplug handler, that new CPU has no per-CPU data infrastructure. The scheduler runs PMU call back function pai_add() to install the PMU support for that CPU before the task is being scheduled on that new CPU. In pai_add() instructions
return a NULL pointer and the result is a kernel panic as variable cpump is used inside that function.
Add CPU hotplug support for CPU add and delete and create the necessary per-CPU data infrastructure during CPU hotplug add processing. Same for CPU hotplug remove. This is done when the CPU is offline to ensure the data structures are available when CPU is made online and tasks are scheduled on it.
[hca@linux.ibm.com: fixup error path in pai_init()]
Detalles técnicos trazas, registros y código del informe original
mp = this_cpu_ptr(pai_root[idx].mapptr);
cpump = mp->mapptr;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: 0.19%
- Percentil entre todas las CVEs puntuadas: 8
- Fecha de la puntuación: 5/10/2026
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)
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{
"id": "CVE-2026-97526",
"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": "9f66572f2889a5e72a9d7e17787e52f03b1f7bd8",
"lessThan": "706e2bf330144995d123dccf32aaf1981ce5abc2",
"versionType": "git"
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{
"status": "affected",
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"lessThan": "9ecc4d033879f7761f2df07e20cd2fbec00fd90b",
"versionType": "git"
}
],
"programFiles": [
"arch/s390/include/asm/pai.h",
"arch/s390/kernel/perf_pai.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3-rc3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/s390/include/asm/pai.h",
"arch/s390/kernel/perf_pai.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-09-25T11:17:02.767",
"references": [
{
"url": "https://git.kernel.org/stable/c/706e2bf330144995d123dccf32aaf1981ce5abc2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9ecc4d033879f7761f2df07e20cd2fbec00fd90b",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/pai: Support CPU hotplug for PMU PAI\n\nThe command 'perf stat -e pai_crypto/CRYPTO_ALL/ -- <command>'\ncrashes the kernel when CPUs are hotplug added during that run.\n\nRoot cause is the missing allocation of per-CPU data structures\nfor that new CPU. The allocation is dynamic and the first\nevent that has task context creates such a structure for\neach online CPU. This is not sufficient. CPUs may be offline\nduring event creation and can be set online during the\nperf run time. For example commands\n\n # echo 0 > /sys/devices/system/cpu/cpu1/online\n # perf stat -e cycles -i -- stress-ng -t10s --matrix X\n # sleep 1\n # echo 1 > /sys/devices/system/cpu/cpu1/online\n\nCurrently without a CPU hotplug handler, that new CPU has no\nper-CPU data infrastructure. The scheduler runs PMU call back\nfunction pai_add() to install the PMU support for that CPU before\nthe task is being scheduled on that new CPU.\nIn pai_add() instructions\n\n mp = this_cpu_ptr(pai_root[idx].mapptr);\n cpump = mp->mapptr;\n\nreturn a NULL pointer and the result is a kernel panic as variable\ncpump is used inside that function.\n\nAdd CPU hotplug support for CPU add and delete and create\nthe necessary per-CPU data infrastructure during CPU hotplug\nadd processing. Same for CPU hotplug remove.\nThis is done when the CPU is offline to ensure the data structures\nare available when CPU is made online and tasks are scheduled on it.\n\n[hca@linux.ibm.com: fixup error path in pai_init()]"
}
],
"lastModified": "2026-09-25T11:17:02.767",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}