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GHSA-H49P-X9P9-Q3F3

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: Delay module ref count for "enable_event" trigger

Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately.

It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug.

Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68177"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:04Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Delay module ref count for \"enable_event\" trigger\n\nTriggers are now delayed from freeing, but can still be triggered until\nafter the RCU grace period has ended. The freeing of the enable_event data\nis put into the private_data_free() callback, but the put of the module\nrefcount is done immediately.\n\nIt is possible that if a module is removed that has an event that would\nenable (or disable) it is still active, it can read the data of the module\nafter it is removed causing a use-after-free bug.\n\nMove the trace_event_put_ref() that releases the module into the delayed\ncallback so that the module can not be removed until any reference to its\nevents are finished.",
  "id": "GHSA-h49p-x9p9-q3f3",
  "modified": "2026-08-14T00:31:52Z",
  "published": "2026-08-10T15:33:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68177"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/159fdc3e01dca5fdbc412fcd8b239895733a270d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e091351b38818ef620d27f44f4bfd625f13afbff"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-68177 (GCVE-0-2026-68177)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-17 05:00

Title

tracing: Delay module ref count for "enable_event" trigger

Summary

In the Linux kernel, the following vulnerability has been resolved: tracing: Delay module ref count for "enable_event" trigger Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately. It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug. Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished.

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 mitre root Scorecard

References

2 references

URL	Tags
https://git.kernel.org/stable/c/159fdc3e01dca5fdb…
https://git.kernel.org/stable/c/e091351b38818ef62…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < 159fdc3e01dca5fdbc412fcd8b239895733a270d (git) Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < e091351b38818ef620d27f44f4bfd625f13afbff (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_events_trigger.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "159fdc3e01dca5fdbc412fcd8b239895733a270d",
              "status": "affected",
              "version": "61d445af0a7c70018111919e47beaaee15653f2f",
              "versionType": "git"
            },
            {
              "lessThan": "e091351b38818ef620d27f44f4bfd625f13afbff",
              "status": "affected",
              "version": "61d445af0a7c70018111919e47beaaee15653f2f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "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: Delay module ref count for \"enable_event\" trigger\n\nTriggers are now delayed from freeing, but can still be triggered until\nafter the RCU grace period has ended. The freeing of the enable_event data\nis put into the private_data_free() callback, but the put of the module\nrefcount is done immediately.\n\nIt is possible that if a module is removed that has an event that would\nenable (or disable) it is still active, it can read the data of the module\nafter it is removed causing a use-after-free bug.\n\nMove the trace_event_put_ref() that releases the module into the delayed\ncallback so that the module can not be removed until any reference to its\nevents are finished."
        }
      ],
      "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 bug is reached only via local `write()` to tracefs event `trigger` files to register/remove `enable_event`/`disable_event` triggers and via local `delete_module(2)`/`rmmod` to unload the referenced trace-event module; no network, adjacent, or physical input path reaches `event_enable_trigger_free()` or `event_enable_trigger()`.\nAC:L - The attacker controls both sides of the race: one thread removes the trigger (premature `trace_event_put_ref()`) and unloads the module while another continuously fires the bound source tracepoint, exploiting the deferred-free window before `tracepoint_synchronize_unregister()` completes in the trigger cleanup kthread.\nPR:L - Trigger registration/removal is gated only by tracefs DAC and `LOCKDOWN_TRACEFS` without `capable()`, which Android/ChromeOS/Perfetto and tracing-group mounts grant to ordinary users; unloading the held module is achievable with `CAP_SYS_MODULE` in a user namespace on permissive kernels loading attacker-controlled modules.\nUI:N - The attacker performs trigger setup/removal, module unload, and source-event generation from their own threads; no separate victim user action is required once tracefs and module privileges are available.\nS:U - The use-after-free corrupts kernel heap/trace structures within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - After premature `trace_event_put_ref()` permits module removal, in-flight `event_enable_trigger()`/`event_enable_count_func()` dereference freed `trace_event_file` and module-resident `trace_event_call` data, exposing reclaimed kernel heap contents.\nI:H - `event_enable_trigger()` performs `set_bit`/`clear_bit` on `enable_data-\u003efile-\u003eflags` through a pointer to a kmem_cache-freed `trace_event_file`, giving a controllable kernel write primitive via heap shaping.\nA:H - Dereferencing freed module/event-file memory from tracepoint context readily causes kernel oops/panic, and the attacker can repeat the race at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:00:18.452Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/159fdc3e01dca5fdbc412fcd8b239895733a270d"
        },
        {
          "url": "https://git.kernel.org/stable/c/e091351b38818ef620d27f44f4bfd625f13afbff"
        }
      ],
      "title": "tracing: Delay module ref count for \"enable_event\" trigger",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68177",
    "datePublished": "2026-08-10T11:59:48.318Z",
    "dateReserved": "2026-07-30T09:28:09.373Z",
    "dateUpdated": "2026-08-17T05:00:18.452Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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-H49P-X9P9-Q3F3

CVE-2026-68177 (GCVE-0-2026-68177)

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