CVE-2026-99237 (GCVE-0-2026-99237)

Vulnerability from cvelistv5 – Published: 2026-11-02 16:06 – Updated: 2026-11-02 16:06
VLAI
Title
tracing: Hold trace_types_lock when resetting last boot data from readers
Summary
In the Linux kernel, the following vulnerability has been resolved: tracing: Hold trace_types_lock when resetting last boot data from readers update_last_data_if_empty() is called from tracing_open() with O_TRUNC, tracing_read_pipe() and tracing_buffers_read() without trace_types_lock. Two readers can both pass the LAST_BOOT test and free module_delta twice, and a module notifier can update module_delta while it is being freed. Take trace_types_lock in those paths and keep the callers that already hold it on an unlocked variant.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6848 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 32dc0042528d385d83bf458e4cf3a49c5110afea , < 92b69f6db640dadc0851762ee2e12db99f083cad (git)
Affected: 32dc0042528d385d83bf458e4cf3a49c5110afea , < d6d991afe775ab7fcf89523a2502b7ca3be56ffd (git)
Affected: 32dc0042528d385d83bf458e4cf3a49c5110afea , < 1f06cfe0b60a878619d1d8efe1cd0f515b7dc2aa (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.60 , ≤ 6.18.* (semver)
Unaffected: 7.2.14 , ≤ 7.2.* (semver)
Unaffected: 7.3.1 , ≤ 7.3.* (semver)
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "kernel/trace/trace.c"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when resetting last boot data from readers\n\nupdate_last_data_if_empty() is called from tracing_open() with O_TRUNC,\ntracing_read_pipe() and tracing_buffers_read() without trace_types_lock.\nTwo readers can both pass the LAST_BOOT test and free module_delta\ntwice, and a module notifier can update module_delta while it is being\nfreed.\n\nTake trace_types_lock in those paths and keep the callers that already\nhold it on an unlocked variant."
        }
      ],
      "metrics": [
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            "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 - Reached only via local tracefs on a last-boot instance: tracing_open() with O_TRUNC on instances/\u003cname\u003e/trace, tracing_read_pipe() on trace_pipe, and tracing_buffers_read() on per_cpu/cpuN/trace_pipe_raw all call update_last_data_if_empty() without trace_types_lock. No remote protocol supplies the trigger.\nAC:L - The attacker controls both sides. Two threads can open() the last-boot instance\u0027s trace with O_TRUNC, or drain the buffer then race tracing_buffers_read() on two trace_pipe_raw fds; both call update_last_data_if_empty() unlocked so each can pass TRACE_ARRAY_FL_LAST_BOOT and kfree_rcu() the same module_delta. The module-notifier race is not required.\nPR:L - tracing_check_open_get_tr() checks only LOCKDOWN_TRACEFS and tracing_disabled, not capable(). trace is TRACE_MODE_WRITE (0640) and trace_pipe/trace_pipe_raw are TRACE_MODE_READ (0440). tracefs uid=/gid= mounts delegate those inodes to a non-root tracing group on Android/Perfetto and embedded systems that use reserve_mem persistent instances.\nUI:N - The attacker opens, truncates, and reads their own last-boot instance descriptors (tracing_open(O_TRUNC) or tracing_buffers_read()). No other user must mount media, enable tracing, or consume the buffer first.\nS:U - The double-free of tr-\u003emodule_delta is in the host kernel heap (update_last_data() kfree_rcu() racing make_mod_delta()). It can escalate locally but does not cross a VM, IOMMU, or sandbox boundary.\nC:H - Two update_last_data() callers can both READ_ONCE(tr-\u003emodule_delta) then kfree_rcu() it, and make_mod_delta() still indexes module_delta-\u003edelta[] after the free. That slab use-after-free of the flex-array object is an arbitrary kernel-memory read primitive.\nI:H - The same double kfree_rcu(module_delta) plus make_mod_delta() writing module_delta-\u003edelta[i] after the object is freed is a heap use-after-free write. Reclaiming that slab yields an arbitrary kernel write and control-flow hijack, not merely a crash.\nA:H - Double-free of module_delta, or make_mod_delta() using it after WRITE_ONCE(tr-\u003emodule_delta, NULL), oopses or panics the kernel. The attacker retriggers that crash through the unlocked tracing_open(O_TRUNC) or tracing_buffers_read() paths."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-02T16:06:42.386Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/92b69f6db640dadc0851762ee2e12db99f083cad"
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        {
          "url": "https://git.kernel.org/stable/c/1f06cfe0b60a878619d1d8efe1cd0f515b7dc2aa"
        }
      ],
      "title": "tracing: Hold trace_types_lock when resetting last boot data from readers",
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  },
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99237",
    "datePublished": "2026-11-02T16:06:42.386Z",
    "dateReserved": "2026-09-25T10:25:14.402Z",
    "dateUpdated": "2026-11-02T16:06:42.386Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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        "cveTags": [],
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            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Hold trace_types_lock when resetting last boot data from readers\n\nupdate_last_data_if_empty() is called from tracing_open() with O_TRUNC,\ntracing_read_pipe() and tracing_buffers_read() without trace_types_lock.\nTwo readers can both pass the LAST_BOOT test and free module_delta\ntwice, and a module notifier can update module_delta while it is being\nfreed.\n\nTake trace_types_lock in those paths and keep the callers that already\nhold it on an unlocked variant."
          }
        ],
        "id": "CVE-2026-99237",
        "lastModified": "2026-11-02T16:17:49.213",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
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      "current_release_date": "2026-11-02T22:24:25+00:00",
      "cve": "CVE-2026-99237",
      "id": "CVE-2026-99237",
      "initial_release_date": "2026-11-02T16:06:42.386000+00:00",
      "product_status:known_not_affected": "280",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: kernel: privilege escalation via race condition in tracing subsystem",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-99237.json",
      "version": "3"
    }
  }
}



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