CVE-2026-74749 (GCVE-0-2026-74749)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:36 – Updated: 2026-08-26 14:36
VLAI
Title
rseq: Prevent hard lockup on granted time slice extension
Summary
In the Linux kernel, the following vulnerability has been resolved: rseq: Prevent hard lockup on granted time slice extension __exit_to_user_mode_loop() invokes rseq_grant_timeslice_extension() with interrupts enabled. If the extension is granted it invokes hrtimer_rearm_deferred_tif() to ensure that a pending deferred hrtimer rearm is handled before exiting to user space. Though this invokes __hrtimer_rearm_deferred() which expects to be invoked with interrupts disabled as it takes hrtimer_cpu_base::lock with raw_spin_lock(). That's a livelock waiting to happen and caught by lockdep: WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit, CPU#1: slice_test WARNING: inconsistent lock state inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. Prevent this by disabling interrupts around the invocation of hrtimer_rearm_deferred_tif() in rseq_grant_timeslice_extension(). [ tglx: Massaged change log ]
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 15dd3a9488557d3e6ebcecacab79f4e56b69ab54 , < 8bbf4405050bc4f98be68082a20efa081ea8ad9b (git)
Affected: 15dd3a9488557d3e6ebcecacab79f4e56b69ab54 , < ada54c2ba652348c590d1ace6a2f4ff77cbbf809 (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.1.10 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "programFiles": [
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Prevent hard lockup on granted time slice extension\n\n__exit_to_user_mode_loop() invokes rseq_grant_timeslice_extension() with\ninterrupts enabled. If the extension is granted it invokes\nhrtimer_rearm_deferred_tif() to ensure that a pending deferred hrtimer\nrearm is handled before exiting to user space.\n\nThough this invokes __hrtimer_rearm_deferred() which expects to be invoked\nwith interrupts disabled as it takes hrtimer_cpu_base::lock with\nraw_spin_lock(). That\u0027s a livelock waiting to happen and caught by lockdep:\n\n    WARNING: ./include/linux/hrtimer_rearm.h:17 at irqentry_exit, CPU#1: slice_test\n    WARNING: inconsistent lock state\n    inconsistent {IN-HARDIRQ-W} -\u003e {HARDIRQ-ON-W} usage.\n\nPrevent this by disabling interrupts around the invocation of\nhrtimer_rearm_deferred_tif() in rseq_grant_timeslice_extension().\n\n[ tglx: Massaged change log ]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-26T14:36:57.763Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/8bbf4405050bc4f98be68082a20efa081ea8ad9b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ada54c2ba652348c590d1ace6a2f4ff77cbbf809"
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      "title": "rseq: Prevent hard lockup on granted time slice extension",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74749",
    "datePublished": "2026-08-26T14:36:57.763Z",
    "dateReserved": "2026-08-15T05:44:03.931Z",
    "dateUpdated": "2026-08-26T14:36:57.763Z",
    "state": "PUBLISHED"
  },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-26T19:45:56+00:00",
      "cve": "CVE-2026-74749",
      "id": "CVE-2026-74749",
      "initial_release_date": "2026-08-26T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: rseq: Prevent hard lockup on granted time slice extension",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74749.json",
      "version": "3"
    }
  }
}



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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.

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.