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CVE-2026-72395 (GCVE-0-2026-72395)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43
VLAI
Title
hwmon: (pmbus) Fix passing events to regulator core
Summary
In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus) Fix passing events to regulator core Sashiko reports: Commit 754bd2b4a084 ("hwmon: (pmbus/core) Protect regulator operations with mutex") introduced a worker to batch regulator events over time using atomic_or(). The delayed worker then passes the combined bitmask unmodified to regulator_notifier_call_chain(). The core regulator subsystem's regulator_handle_critical() function evaluates the event parameter using a strict switch statement. If multiple distinct faults occur before the worker runs (e.g., REGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined bitmask fails to match any case. This leaves the reason as NULL and completely bypasses the critical hw_protection_trigger(). Fix the problem by passing events bit by bit to the regulator event handler.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: b26849cffaa7c43355b82e9bef3725e786973a1a , < 2106bf4056858fcce3624e0c51f6fee4d41d3f2f (git)
Affected: acf04e2863132f6d9222f71f3a76fb9782cbe061 , < 48fe43666950efefb7ac5fbdc012c1b3604096bf (git)
Affected: 4e9d723d9f198b86f6882a84c501ba1f39e8d055 , < 489291b6b56978cc50d34e8e13f9636ea296ba8a (git)
Affected: 754bd2b4a084b90b5e7b630e1f423061a9b9b761 , < b0ff6b6ae9c5183ef701ece7016698bde5a5bfba (git)
Affected: 754bd2b4a084b90b5e7b630e1f423061a9b9b761 , < 9ef7dacd44216bf5ea05c8aef49eba4d145f4047 (git)
Affected: 2c77ae315f3ce9d2c8e1609be74c9358c1fe4e07 (git)
Affected: 6.6.143 , < 6.6.145 (semver)
Affected: 6.12.92 , < 6.12.97 (semver)
Affected: 6.18.21 , < 6.18.40 (semver)
Affected: 6.19.11 , < 6.20 (semver)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (pmbus) Fix passing events to regulator core\n\nSashiko reports:\n\nCommit 754bd2b4a084 (\"hwmon: (pmbus/core) Protect regulator operations with\nmutex\") introduced a worker to batch regulator events over time using\natomic_or(). The delayed worker then passes the combined bitmask unmodified\nto regulator_notifier_call_chain().\n\nThe core regulator subsystem\u0027s regulator_handle_critical() function\nevaluates the event parameter using a strict switch statement. If\nmultiple distinct faults occur before the worker runs (e.g.,\nREGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined\nbitmask fails to match any case. This leaves the reason as NULL and\ncompletely bypasses the critical hw_protection_trigger().\n\nFix the problem by passing events bit by bit to the regulator event\nhandler."
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              "value": "AV:L - The flaw is only reachable through the PMBus SMBALERT threaded IRQ handler (pmbus_fault_handler) that reads hardware fault status over I2C; there is no network, adjacent-radio, or direct physical-device API path, but local actors on PMBus-equipped servers, routers, and embedded boards can induce multi-fault conditions.\nAC:L - _pmbus_get_flags() ORs multiple REGULATOR_EVENT_* bits from a single STATUS read, and pmbus_regulator_notify() further batches concurrent IRQs via atomic_or() before the worker runs, so combined masks like UNDER_VOLTAGE|OVER_CURRENT are produced deterministically without races or layout dependencies the attacker cannot influence.\nPR:L - Triggering the IRQ requires causing real PMBus regulator fault bits (e.g., over-current plus under-voltage during supply stress), which an unprivileged local user can induce through heavy workload and power instability on affected platforms; CAP_NET_ADMIN/user-namespace tricks are not needed and no init-namespace root capability is required.\nUI:N - Once fault conditions are present the SMBALERT IRQ and workqueue fire automatically through pmbus_fault_handler and pmbus_regulator_notify_worker; no separate victim action such as mounting media, plugging hardware, or approving a prompt is required.\nS:U - The impact is bypassing kernel hw_protection_trigger() orderly shutdown/reboot for system-critical PMBus regulators on the same host; it does not cross VM, IOMMU, or sandbox security boundaries and is not a guest-to-host escape.\nC:N - This is a notifier bit-mask logic error that leaves regulator_handle_critical() with a NULL reason; there is no kernel memory corruption, use-after-free, or out-of-bounds access that could disclose pointers or arbitrary memory.\nI:H - When multiple distinct fault events are combined, hw_protection_trigger() is completely skipped for system-critical regulators, defeating the kernel\u0027s mandatory emergency shutdown policy and allowing continued operation under simultaneous critical under-voltage/over-current/fail conditions that can corrupt power hardware.\nA:H - Bypassing hw_protection_trigger() during simultaneous critical PMBus regulator faults prevents the intended emergency orderly_poweroff/reboot, leaving telecom, data-center, and embedded systems running under dangerous rail conditions that can cause hardware failure, forced resets, and sustained denial of service."
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    "datePublished": "2026-08-15T05:56:22.400Z",
    "dateReserved": "2026-08-09T03:40:39.924Z",
    "dateUpdated": "2026-08-17T05:43:38.599Z",
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If\\nmultiple distinct faults occur before the worker runs (e.g.,\\nREGULATOR_EVENT_UNDER_VOLTAGE | REGULATOR_EVENT_OVER_CURRENT), the combined\\nbitmask fails to match any case. 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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-18T15:16:37+00:00",
      "cve": "CVE-2026-72395",
      "id": "CVE-2026-72395",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: hwmon: (pmbus) Fix passing events to regulator core",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72395.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.

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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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