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vuln-cve/data/2025/22xxx/CVE-2025-22094.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2025-22094",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2024-12-29T08:45:45.818Z",
"datePublished": "2025-04-16T14:12:45.512Z",
"dateUpdated": "2026-08-05T11:56:45.289Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-05T11:56:45.289Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/perf: Fix ref-counting on the PMU 'vpa_pmu'\n\nCommit 176cda0619b6 (\"powerpc/perf: Add perf interface to expose vpa\ncounters\") introduced 'vpa_pmu' to expose Book3s-HV nested APIv2 provided\nL1<->L2 context switch latency counters to L1 user-space via\nperf-events. However the newly introduced PMU named 'vpa_pmu' doesn't\nassign ownership of the PMU to the module 'vpa_pmu'. Consequently the\nmodule 'vpa_pmu' can be unloaded while one of the perf-events are still\nactive, which can lead to kernel oops and panic of the form below on a\nPseries-LPAR:\n\nBUG: Kernel NULL pointer dereference on read at 0x00000058\n<snip>\n NIP [c000000000506cb8] event_sched_out+0x40/0x258\n LR [c00000000050e8a4] __perf_remove_from_context+0x7c/0x2b0\n Call Trace:\n [c00000025fc3fc30] [c00000025f8457a8] 0xc00000025f8457a8 (unreliable)\n [c00000025fc3fc80] [fffffffffffffee0] 0xfffffffffffffee0\n [c00000025fc3fcd0] [c000000000501e70] event_function+0xa8/0x120\n<snip>\n Kernel panic - not syncing: Aiee, killing interrupt handler!\n\nFix this by adding the module ownership to 'vpa_pmu' so that the module\n'vpa_pmu' is ref-counted and prevented from being unloaded when perf-events\nare initialized."
}
],
"metrics": [
{
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
"baseScore": 7.3,
"baseSeverity": "HIGH"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerability is reached entirely through local syscalls — `perf_event_open(2)` to bind an event to the `vpa_pmu` PMU and `delete_module(2)` to unload the module. There is no network or remote-peer input path to this powerpc perf driver.\nAC:L - The attacker deterministically sets up the condition by holding a `vpa_pmu` perf event open indefinitely; there is no race to win and no memory layout beyond the attacker's influence, so any subsequent module unload reliably hits a live dangling event.\nPR:L - The missing module reference is taken (or rather, not taken) on behalf of an ordinary local user calling `perf_event_open` — no capability is checked in `vpa_pmu_event_init()`, and the `perf_allow_kernel()` gate is open to unprivileged users whenever `kernel.perf_event_paranoid <= 1`, a routine setting on the profiling/KVM-on-PowerVM hosts where this PMU is deployed.\nUI:R - Triggering the use-after-free requires the module to actually be unloaded, and `delete_module(2)` demands `CAP_SYS_MODULE` in the initial user namespace, which the low-privileged attacker cannot obtain via user namespaces — so an administrator's `rmmod vpa_pmu` (routine after a perf measurement session) is the required second-party action.\nS:U - The freed `struct pmu` and module text belong to the same kernel that the attacker's process already runs under, so impact stays within one security authority. Although `vpa_pmu` relates to KVM-on-PowerVM, the driver only runs on the L1 LPAR and the corruption never crosses the guest/host boundary.\nC:H - This is a use-after-free of a `struct pmu` living in vfree'd module memory, including a stale `pmu->pmu_disable_count` percpu pointer that is read on every event schedule; reclaiming that memory (e.g. by loading another module) turns the dangling reads into a kernel memory disclosure primitive.\nI:H - The dangling `event->pmu` still carries `->add`, `->del` and `->read` function pointers into freed module text, so the perf core makes indirect calls through attacker-influenceable reclaimed memory — a control-flow hijack primitive, not merely stale data.\nA:H - The commit documents the concrete outcome: a NULL pointer dereference in `event_sched_out()` reached from `__perf_remove_from_context()`, escalating to `Kernel panic - not syncing: Aiee, killing interrupt handler!` — a full system crash."
}
]
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/powerpc/perf/vpa-pmu.c"
],
"versions": [
{
"version": "176cda0619b6c17a553625f6e2fcbc3981ad667d",
"lessThan": "70ea7c5189197c6f5acdcfd8a2651be2c41e2faa",
"status": "affected",
"versionType": "git"
},
{
"version": "176cda0619b6c17a553625f6e2fcbc3981ad667d",
"lessThan": "6cf045b51e2c5721db7e55305f09ee32741e00f9",
"status": "affected",
"versionType": "git"
},
{
"version": "176cda0619b6c17a553625f6e2fcbc3981ad667d",
"lessThan": "ff99d5b6a246715f2257123cdf6c4a29cb33aa78",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/powerpc/perf/vpa-pmu.c"
],
"versions": [
{
"version": "6.13",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.13",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.13.11",
"lessThanOrEqual": "6.13.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.14.2",
"lessThanOrEqual": "6.14.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.15",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.13",
"versionEndExcluding": "6.13.11"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.13",
"versionEndExcluding": "6.14.2"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.13",
"versionEndExcluding": "6.15"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/70ea7c5189197c6f5acdcfd8a2651be2c41e2faa"
},
{
"url": "https://git.kernel.org/stable/c/6cf045b51e2c5721db7e55305f09ee32741e00f9"
},
{
"url": "https://git.kernel.org/stable/c/ff99d5b6a246715f2257123cdf6c4a29cb33aa78"
}
],
"title": "powerpc/perf: Fix ref-counting on the PMU 'vpa_pmu'",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
}
}