CVE-2026-64556 (GCVE-0-2026-64556)
Vulnerability from cvelistv5
Published
2026-07-29 08:01
Modified
2026-08-17 04:57
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
perf/core: Detach event groups during remove_on_exec
perf_event_remove_on_exec() removes events by calling
perf_event_exit_event(). For top-level events, this removes the event from
the context with DETACH_EXIT only.
This can leave inconsistent group state when a removed event is a group
leader and the group contains siblings without remove_on_exec. If the group
was active, the surviving siblings can remain active and attached to the
removed leader's sibling list, but are no longer represented by a valid
group leader on the PMU context active lists.
A later close of the removed leader uses DETACH_GROUP and can promote the
still-active siblings from this stale group state. The next schedule-in can
then add an already-linked active_list entry again, corrupting the PMU
context active list.
With DEBUG_LIST enabled, this is caught as a list_add double-add in
merge_sched_in().
Fix this by detaching group relationships when remove_on_exec removes an
event. This preserves the existing task-exit and revoke behavior, while
ensuring surviving siblings are ungrouped before the removed event leaves
the context.
References
Impacted products
{
"containers": {
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"versions": [
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"status": "unaffected",
"version": "0",
"versionType": "semver"
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"status": "unaffected",
"version": "6.6.145",
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{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.96",
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{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
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{
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"status": "unaffected",
"version": "7.1.4",
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
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}
],
"cpeApplicability": [
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"nodes": [
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"vulnerable": true
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"negate": false,
"operator": "OR"
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Detach event groups during remove_on_exec\n\nperf_event_remove_on_exec() removes events by calling\nperf_event_exit_event(). For top-level events, this removes the event from\nthe context with DETACH_EXIT only.\n\nThis can leave inconsistent group state when a removed event is a group\nleader and the group contains siblings without remove_on_exec. If the group\nwas active, the surviving siblings can remain active and attached to the\nremoved leader\u0027s sibling list, but are no longer represented by a valid\ngroup leader on the PMU context active lists.\n\nA later close of the removed leader uses DETACH_GROUP and can promote the\nstill-active siblings from this stale group state. The next schedule-in can\nthen add an already-linked active_list entry again, corrupting the PMU\ncontext active list.\n\nWith DEBUG_LIST enabled, this is caught as a list_add double-add in\nmerge_sched_in().\n\nFix this by detaching group relationships when remove_on_exec removes an\nevent. This preserves the existing task-exit and revoke behavior, while\nensuring surviving siblings are ungrouped before the removed event leaves\nthe context."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerability is triggered entirely through local syscalls \u2014 `perf_event_open(2)` to build the event group and `execve(2)`/`close(2)` to trigger the stale-group corruption. No network or physical vector is involved.\nAC:L - The attacker controls the entire deterministic sequence: create a pinned/enabled group with a `remove_on_exec` leader plus non-`remove_on_exec` siblings, exec, then close the leader. No race the attacker cannot influence is required.\nPR:L - An unprivileged user can open perf events on their own task with `exclude_kernel=1` even at the default `perf_event_paranoid=2`, requiring no capability. Basic local user access suffices.\nUI:N - The attacking process performs every step itself (open, exec, close); no action from any other user is needed.\nS:U - The corruption stays within the kernel\u0027s own security authority (PMU context list in kernel heap); it does not cross a hypervisor/IOMMU/sandbox boundary.\nC:H - Corrupting the doubly-linked active list of `perf_event` objects yields pointer manipulation over heap-embedded list nodes, which can be leveraged to read adjacent/freed kernel memory for information disclosure.\nI:H - A double `list_add`/subsequent list operations on a corrupted list provide write-what-where-style primitives against attacker-influenceable heap objects, enabling arbitrary modification and control-flow hijack.\nA:H - The list corruption reliably produces a kernel crash/oops (caught as a list_add double-add under DEBUG_LIST, silent corruption and panic otherwise), causing denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:57:34.489Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2"
},
{
"url": "https://git.kernel.org/stable/c/39358e856fb89e62e3c8d7389a2dc4ec33dbe90e"
},
{
"url": "https://git.kernel.org/stable/c/a2d5d3ee7b6e3953114726b1521e62123ab5b043"
},
{
"url": "https://git.kernel.org/stable/c/06ccef0434e98058ddae7bcebc901f93d22b7653"
},
{
"url": "https://git.kernel.org/stable/c/037a3c43edfb597665dd34457cd22b14692f2ba3"
}
],
"title": "perf/core: Detach event groups during remove_on_exec",
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64556",
"datePublished": "2026-07-29T08:01:46.864Z",
"dateReserved": "2026-07-19T15:36:31.796Z",
"dateUpdated": "2026-08-17T04:57:34.489Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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