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GHSA-P3CM-8J25-92W5

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-14 00:31

Details

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

tracing: Fix use-after-free freeing trigger private data

Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free().

event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free.

The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-removal write returns, otherwise a following command races in and the synthetic-event removal fails with -EBUSY, as the trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait with the correct barrier - tracepoint_synchronize_unregister(), matching the free kthread - before freeing.

The enable trigger has no such synchronous requirement, and a blocking synchronize there would re-serialize the path that commit deliberately deferred. Give it an optional private_data_free() callback that the free kthread runs after its grace period, and free enable_data from there.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68283"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:17Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free freeing trigger private data\n\nCommit 61d445af0a7c (\"tracing: Add bulk garbage collection of freeing\nevent_trigger_data\") moved the kfree() of event_trigger_data to a kthread\nthat runs tracepoint_synchronize_unregister() before freeing. That removed\nthe synchronization the trigger .free callbacks used to get implicitly and\ninline from trigger_data_free().\n\nevent_hist_trigger_free(), event_hist_trigger_named_free() and\nevent_enable_trigger_free() free their satellite data (hist_data, cmd_ops,\nenable_data) right after trigger_data_free() returns. With the\nsynchronization now deferred to the kthread, a concurrent tracepoint\nhandler can still reach that data through the list_del_rcu()\u0027d trigger,\ncausing a use-after-free.\n\nThe histogram teardown must stay synchronous: remove_hist_vars() and\nunregister_field_var_hists() have to detach a synthetic event from the\nhistogram before the trigger-removal write returns, otherwise a following\ncommand races in and the synthetic-event removal fails with -EBUSY, as the\ntrigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait\nwith the correct barrier - tracepoint_synchronize_unregister(), matching\nthe free kthread - before freeing.\n\nThe enable trigger has no such synchronous requirement, and a blocking\nsynchronize there would re-serialize the path that commit deliberately\ndeferred. Give it an optional private_data_free() callback that the free\nkthread runs after its grace period, and free enable_data from there.",
  "id": "GHSA-p3cm-8j25-92w5",
  "modified": "2026-08-14T00:31:54Z",
  "published": "2026-08-10T15:33:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68283"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68283 (GCVE-0-2026-68283)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:02 – Updated: 2026-08-17 05:02

Title

tracing: Fix use-after-free freeing trigger private data

Summary

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix use-after-free freeing trigger private data Commit 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data") moved the kfree() of event_trigger_data to a kthread that runs tracepoint_synchronize_unregister() before freeing. That removed the synchronization the trigger .free callbacks used to get implicitly and inline from trigger_data_free(). event_hist_trigger_free(), event_hist_trigger_named_free() and event_enable_trigger_free() free their satellite data (hist_data, cmd_ops, enable_data) right after trigger_data_free() returns. With the synchronization now deferred to the kthread, a concurrent tracepoint handler can still reach that data through the list_del_rcu()'d trigger, causing a use-after-free. The histogram teardown must stay synchronous: remove_hist_vars() and unregister_field_var_hists() have to detach a synthetic event from the histogram before the trigger-removal write returns, otherwise a following command races in and the synthetic-event removal fails with -EBUSY, as the trigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait with the correct barrier - tracepoint_synchronize_unregister(), matching the free kthread - before freeing. The enable trigger has no such synchronous requirement, and a blocking synchronize there would re-serialize the path that commit deliberately deferred. Give it an optional private_data_free() callback that the free kthread runs after its grace period, and free enable_data from there.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/b9c8a1400a3bf633f…
https://git.kernel.org/stable/c/79097812153b826fc…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < b9c8a1400a3bf633f32820d184f3e05fed0f4af7 (git) Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < 79097812153b826fc156a2930ec8a90ed9edf4a2 (git)
Linux	Linux	Affected: 6.19 Unaffected: 0 , < 6.19 (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/trace.h",
            "kernel/trace/trace_events_hist.c",
            "kernel/trace/trace_events_trigger.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b9c8a1400a3bf633f32820d184f3e05fed0f4af7",
              "status": "affected",
              "version": "61d445af0a7c70018111919e47beaaee15653f2f",
              "versionType": "git"
            },
            {
              "lessThan": "79097812153b826fc156a2930ec8a90ed9edf4a2",
              "status": "affected",
              "version": "61d445af0a7c70018111919e47beaaee15653f2f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/trace/trace.h",
            "kernel/trace/trace_events_hist.c",
            "kernel/trace/trace_events_trigger.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Fix use-after-free freeing trigger private data\n\nCommit 61d445af0a7c (\"tracing: Add bulk garbage collection of freeing\nevent_trigger_data\") moved the kfree() of event_trigger_data to a kthread\nthat runs tracepoint_synchronize_unregister() before freeing. That removed\nthe synchronization the trigger .free callbacks used to get implicitly and\ninline from trigger_data_free().\n\nevent_hist_trigger_free(), event_hist_trigger_named_free() and\nevent_enable_trigger_free() free their satellite data (hist_data, cmd_ops,\nenable_data) right after trigger_data_free() returns. With the\nsynchronization now deferred to the kthread, a concurrent tracepoint\nhandler can still reach that data through the list_del_rcu()\u0027d trigger,\ncausing a use-after-free.\n\nThe histogram teardown must stay synchronous: remove_hist_vars() and\nunregister_field_var_hists() have to detach a synthetic event from the\nhistogram before the trigger-removal write returns, otherwise a following\ncommand races in and the synthetic-event removal fails with -EBUSY, as the\ntrigger-synthetic-eprobe.tc selftest catches. Make those callbacks wait\nwith the correct barrier - tracepoint_synchronize_unregister(), matching\nthe free kthread - before freeing.\n\nThe enable trigger has no such synchronous requirement, and a blocking\nsynchronize there would re-serialize the path that commit deliberately\ndeferred. Give it an optional private_data_free() callback that the free\nkthread runs after its grace period, and free enable_data from there."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Placeholder.\nAC:L - The attacker controls both sides of the race: one thread writes \u0027!hist:\u0027/\u0027!enable_event:\u0027 to remove the trigger while another continuously fires the traced event, so an in-flight event_triggers_call() reader reliably touches hist_data/enable_data after they are freed inline.\nPR:L - Registering and removing triggers only needs write access to tracefs (TRACE_MODE_WRITE, DAC plus LOCKDOWN_TRACEFS, no capable() gate), which realistic deployments such as Android/perfetto, ChromeOS and gid=tracing mounts grant to unprivileged tracing users.\nUI:N - The attacker performs both the trigger removal and the event generation itself; no separate victim action is required.\nS:U - The use-after-free corrupts kernel heap memory within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - A concurrent handler dereferences the freed hist_trigger_data (n_keys, fields[], key_size, tracing_map) and the freed enable_trigger_data-\u003efile, so reclaimed heap contents are read and can be reflected back through histogram output, giving arbitrary kernel memory disclosure.\nI:H - event_hist_trigger() writes into freed tracing_map elements and event_enable_trigger() writes event-file flags through a pointer read from freed enable_data, so heap spraying the reclaimed objects yields a controlled write primitive suitable for privilege escalation.\nA:H - Use-after-free of hist_data/cmd_ops/enable_data readily causes oops or panic in tracepoint context even without successful exploitation, and the race can be re-triggered at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:02:18.147Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b9c8a1400a3bf633f32820d184f3e05fed0f4af7"
        },
        {
          "url": "https://git.kernel.org/stable/c/79097812153b826fc156a2930ec8a90ed9edf4a2"
        }
      ],
      "title": "tracing: Fix use-after-free freeing trigger private data",
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        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68283",
    "datePublished": "2026-08-10T12:02:15.088Z",
    "dateReserved": "2026-07-30T09:28:09.379Z",
    "dateUpdated": "2026-08-17T05:02:18.147Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-P3CM-8J25-92W5

CVE-2026-68283 (GCVE-0-2026-68283)

Tags

Sightings

Nomenclature