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GHSA-79F3-6WM5-9QVC

Vulnerability from github – Published: 2026-09-17 18:32 – Updated: 2026-09-17 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

perf/x86/intel/uncore: Fix uncore_box ref/unref ordering

In uncore_event_cpu_online(), uncore_box_ref() was called before uncore_change_context(). uncore_box_ref() gates on box->cpu >= 0, but box->cpu is still -1 at that point because uncore_change_context() has not run yet. As a result, the box is never initialized on the first CPU to come online in a die, leaving it permanently uninitialized in the single-CPU-per-die case.

Thus, box->refcnt is one count below the true value, and in the CPU offline path, the box will be torn down on the second-to-last CPU.

In uncore_event_cpu_offline(), uncore_box_unref() was called after uncore_change_context(), so box->cpu is already -1 when the collector CPU goes offline, which prevents it from tearing down the box.

Fix by swapping the call order in both paths so that uncore_box_{ref,unref}() runs at the point where box->cpu reflects the correct context.

Move allocate_boxes() out of uncore_box_ref() to enable this reordering.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93181"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-17T17:18:14Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix uncore_box ref/unref ordering\n\nIn uncore_event_cpu_online(), uncore_box_ref() was called before\nuncore_change_context().  uncore_box_ref() gates on box-\u003ecpu \u003e= 0,\nbut box-\u003ecpu is still -1 at that point because uncore_change_context()\nhas not run yet.  As a result, the box is never initialized on the\nfirst CPU to come online in a die, leaving it permanently\nuninitialized in the single-CPU-per-die case.\n\nThus, box-\u003erefcnt is one count below the true value, and in the CPU\noffline path, the box will be torn down on the second-to-last CPU.\n\nIn uncore_event_cpu_offline(), uncore_box_unref() was called after\nuncore_change_context(), so box-\u003ecpu is already -1 when the collector\nCPU goes offline, which prevents it from tearing down the box.\n\nFix by swapping the call order in both paths so that\nuncore_box_{ref,unref}() runs at the point where box-\u003ecpu reflects\nthe correct context.\n\nMove allocate_boxes() out of uncore_box_ref() to enable this\nreordering.",
  "id": "GHSA-79f3-6wm5-9qvc",
  "modified": "2026-09-17T18:32:13Z",
  "published": "2026-09-17T18:32:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93181"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/174f0582e38abe03b88e15f04bfe58490f88cb19"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/64aa1bb4017d598828c6d8cd718f43daf2a83375"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-93181 (GCVE-0-2026-93181)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:12 – Updated: 2026-09-17 16:12

Title

perf/x86/intel/uncore: Fix uncore_box ref/unref ordering

Summary

In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel/uncore: Fix uncore_box ref/unref ordering In uncore_event_cpu_online(), uncore_box_ref() was called before uncore_change_context(). uncore_box_ref() gates on box->cpu >= 0, but box->cpu is still -1 at that point because uncore_change_context() has not run yet. As a result, the box is never initialized on the first CPU to come online in a die, leaving it permanently uninitialized in the single-CPU-per-die case. Thus, box->refcnt is one count below the true value, and in the CPU offline path, the box will be torn down on the second-to-last CPU. In uncore_event_cpu_offline(), uncore_box_unref() was called after uncore_change_context(), so box->cpu is already -1 when the collector CPU goes offline, which prevents it from tearing down the box. Fix by swapping the call order in both paths so that uncore_box_{ref,unref}() runs at the point where box->cpu reflects the correct context. Move allocate_boxes() out of uncore_box_ref() to enable this reordering.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/64aa1bb4017d59882…
https://git.kernel.org/stable/c/174f0582e38abe03b…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c74443d92f68f07c03ae242ced554b749e6c6736 , < 64aa1bb4017d598828c6d8cd718f43daf2a83375 (git) Affected: c74443d92f68f07c03ae242ced554b749e6c6736 , < 174f0582e38abe03b88e15f04bfe58490f88cb19 (git)
Linux	Linux	Affected: 6.11 Unaffected: 0 , < 6.11 (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
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          "programFiles": [
            "arch/x86/events/intel/uncore.c"
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
            },
            {
              "lessThan": "174f0582e38abe03b88e15f04bfe58490f88cb19",
              "status": "affected",
              "version": "c74443d92f68f07c03ae242ced554b749e6c6736",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/events/intel/uncore.c"
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          "vendor": "Linux",
          "versions": [
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              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
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      ],
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          "nodes": [
            {
              "cpeMatch": [
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                  "vulnerable": true
                },
                {
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                }
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/uncore: Fix uncore_box ref/unref ordering\n\nIn uncore_event_cpu_online(), uncore_box_ref() was called before\nuncore_change_context().  uncore_box_ref() gates on box-\u003ecpu \u003e= 0,\nbut box-\u003ecpu is still -1 at that point because uncore_change_context()\nhas not run yet.  As a result, the box is never initialized on the\nfirst CPU to come online in a die, leaving it permanently\nuninitialized in the single-CPU-per-die case.\n\nThus, box-\u003erefcnt is one count below the true value, and in the CPU\noffline path, the box will be torn down on the second-to-last CPU.\n\nIn uncore_event_cpu_offline(), uncore_box_unref() was called after\nuncore_change_context(), so box-\u003ecpu is already -1 when the collector\nCPU goes offline, which prevents it from tearing down the box.\n\nFix by swapping the call order in both paths so that\nuncore_box_{ref,unref}() runs at the point where box-\u003ecpu reflects\nthe correct context.\n\nMove allocate_boxes() out of uncore_box_ref() to enable this\nreordering."
        }
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        "dateUpdated": "2026-09-17T16:12:08.716Z",
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    "datePublished": "2026-09-17T16:12:08.716Z",
    "dateReserved": "2026-09-17T16:02:15.091Z",
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    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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