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

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-17 05:00
VLAI
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
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < 159fdc3e01dca5fdbc412fcd8b239895733a270d (git)
Affected: 61d445af0a7c70018111919e47beaaee15653f2f , < e091351b38818ef620d27f44f4bfd625f13afbff (git)
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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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              "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."
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        "dateUpdated": "2026-08-17T05:00:18.452Z",
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        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/e091351b38818ef620d27f44f4bfd625f13afbff"
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    "dateReserved": "2026-07-30T09:28:09.373Z",
    "dateUpdated": "2026-08-17T05:00:18.452Z",
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      "cve": "CVE-2026-68177",
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      "title": "SUSE CVE CVE-2026-68177",
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    }
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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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.
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  • 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.


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