CVE-2026-98552
In the Linux kernel, the following vulnerability has been resolved:
perf/core: Fix a refcount leak in attach_perf_ctx_data()
The attach_perf_ctx_data() can race on global and !global cases. The global case is protected by global_ctx_data_rwsem and shares a single reference count using perf_ctx_data.global field.
But when it races with !global case, it may miss to set the global field and result in a reference count leak.
CPU1 CPU2 ---------------------------------------------------------------- attach_task_ctx_data(.global=1) attach_task_ctx_data(.global=0) cd1 = alloc_perf_ctx_data(); cd2 = alloc_perf_ctx_data(); // { .global = 0, .refcount = 1 };
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Then later detach_global_ctx_data() will see the data but it's not marked as global, so it won't call detach_task_ctx_data().
Technical details traces, logs and code from the original report
try_cmpxchg(); // success,
// task->perf_ctx_data = cd2
try_cmpxhg(); // fail; old = cd2
refcount_inc_not_zero(&old->refcount); // success
// old.refcount = 2
free_perf_ctx_data(cd1);CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.20 %
- Percentile among all scored CVEs
- 9
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Raw JSON (NVD)
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{
"id": "CVE-2026-98552",
"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": "506e64e710ff9573fd2b86686528762b7901b5e4",
"lessThan": "23250517cd475367653f1e99396967f54c6f1b7c",
"versionType": "git"
},
{
"status": "affected",
"version": "506e64e710ff9573fd2b86686528762b7901b5e4",
"lessThan": "5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72",
"versionType": "git"
},
{
"status": "affected",
"version": "506e64e710ff9573fd2b86686528762b7901b5e4",
"lessThan": "cca4980630b3c7a85f53cb43c6018184ce5d4e37",
"versionType": "git"
}
],
"programFiles": [
"kernel/events/core.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"kernel/events/core.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:07.267",
"references": [
{
"url": "https://git.kernel.org/stable/c/23250517cd475367653f1e99396967f54c6f1b7c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/5286d4eb5cd7e10d7d93c3cc596e18bc8ad80f72",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/cca4980630b3c7a85f53cb43c6018184ce5d4e37",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Fix a refcount leak in attach_perf_ctx_data()\n\nThe attach_perf_ctx_data() can race on global and !global cases. The\nglobal case is protected by global_ctx_data_rwsem and shares a single\nreference count using perf_ctx_data.global field.\n\nBut when it races with !global case, it may miss to set the global field\nand result in a reference count leak.\n\n CPU1 CPU2\n ----------------------------------------------------------------\n attach_task_ctx_data(.global=1) attach_task_ctx_data(.global=0)\n cd1 = alloc_perf_ctx_data(); cd2 = alloc_perf_ctx_data();\n // { .global = 0, .refcount = 1 };\n\n try_cmpxchg(); // success,\n // task->perf_ctx_data = cd2\n try_cmpxhg(); // fail; old = cd2\n refcount_inc_not_zero(&old->refcount); // success\n // old.refcount = 2\n free_perf_ctx_data(cd1);\n\nThen later detach_global_ctx_data() will see the data but it's not\nmarked as global, so it won't call detach_task_ctx_data()."
}
],
"lastModified": "2026-10-19T10:19:11.487",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}