CVE-2026-74302 (GCVE-0-2026-74302)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:45
VLAI
Title
Bluetooth: hci_core: Fix UAF in hci_unregister_dev()
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Fix UAF in hci_unregister_dev() hci_unregister_dev() does not disable cmd_timer and ncmd_timer before the hci_dev structure is freed. If a timeout fires during device teardown, the callback dereferences freed memory (including the hdev->reset function pointer), leading to a use-after-free. Add disable_delayed_work_sync() calls alongside the existing disable_work_sync() calls to ensure both timers are fully quiesced before teardown proceeds.
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: 0d151a103775dd9645c78c97f77d6e2a5298d913 , < 48c7ad6afcc58c2cda11fed39791708103b6a644 (git)
Affected: 0d151a103775dd9645c78c97f77d6e2a5298d913 , < a0fd1086a57b982f8c24ae4ab165c2af39fe1735 (git)
Affected: 0d151a103775dd9645c78c97f77d6e2a5298d913 , < 672d52d9412252e61b8de8d773ccdf5a277cf540 (git)
Affected: 0d151a103775dd9645c78c97f77d6e2a5298d913 , < 5edcc018fa6e80b2c478454a4a8229c23d67c181 (git)
Affected: 48542881997e17b49dc16b93fe910e0cfcf7a9f9 (git)
Affected: 9cfc84b1d464cc024286f42a090718f9067b80ed (git)
Affected: ddeda6ca5f218b668b560d90fc31ae469adbfd92 (git)
Affected: d2ce562a5aff1dcd0c50d9808ea825ef90da909f (git)
Affected: 96600c2e5ee8213dbab5df1617293d8e847bb4fa (git)
Affected: d6cbce18370641a21dd889e8613d8153df15eb39 (git)
Affected: 3f939bd73fed12dddc2a32a76116c19ca47c7678 (git)
Affected: 4.19.319 , < 4.20 (semver)
Affected: 5.4.281 , < 5.5 (semver)
Affected: 5.10.223 , < 5.11 (semver)
Affected: 5.15.164 , < 5.16 (semver)
Affected: 6.1.101 , < 6.2 (semver)
Affected: 6.6.42 , < 6.7 (semver)
Affected: 6.9.11 , < 6.10 (semver)
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Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (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\nBluetooth: hci_core: Fix UAF in hci_unregister_dev()\n\nhci_unregister_dev() does not disable cmd_timer and ncmd_timer\nbefore the hci_dev structure is freed. If a timeout fires\nduring device teardown, the callback dereferences freed memory\n(including the hdev-\u003ereset function pointer), leading to a\nuse-after-free.\n\nAdd disable_delayed_work_sync() calls alongside the existing\ndisable_work_sync() calls to ensure both timers are fully\nquiesced before teardown proceeds."
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            "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"
          },
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              "lang": "en",
              "value": "AV:L - The UAF is reached only during hci_unregister_dev() teardown (e.g. closing /dev/vhci, USB/btusb disconnect, hci_ldisc detach, or driver removal); adjacent Bluetooth peers can arm cmd_timer/ncmd_timer via HCI timeouts but cannot invoke unregister, so exploitation requires local device/syscall access.\nAC:L - An attacker controls both sides of the race\u2014arming cmd_timer (2s) or ncmd_timer (4s) by withholding HCI command completions while closing /dev/vhci to run hci_unregister_dev(), and disable_work_sync(cmd_work) can queue cmd_timer immediately before teardown; the cycle is repeatable.\nPR:L - vhci_open() has no capable() check, so any principal granted /dev/vhci (syzkaller, containers, Android bluetooth uid, permissive udev) can create/destroy virtual HCI controllers and inject frames without init-namespace root, matching prior hci_unregister_dev teardown UAF scores.\nUI:N - The attacker performs device creation, HCI traffic injection, and teardown from its own process via open/write/close on /dev/vhci or equivalent local transport; no victim interaction or cooperation is required beyond existing device-node access.\nS:U - Corruption is confined to kernel slab memory and workqueue/timer state within the same kernel security authority; exploitation yields standard kernel privilege escalation, not VM escape, IOMMU bypass, or cross-sandbox boundary crossing.\nC:H - hci_cmd_timeout() and hci_ncmd_timeout() dereference the freed hci_dev (req_skb, flags, workqueue, name) after kfree(); UAF on the hci_dev slab enables controlled reallocation and arbitrary kernel memory read/pointer disclosure via heap spraying.\nI:H - hci_cmd_timeout() invokes the freed hdev-\u003ereset function pointer and re-queues cmd_work on hdev-\u003eworkqueue; attacker-controlled contents in the reclaimed hci_dev object provide arbitrary write and control-flow hijack primitives per kernel UAF scoring guidance.\nA:H - Timer callbacks operating on freed hci_dev memory cause KASAN slab-use-after-free reports, kernel oops/panic, and can queue work onto destroyed workqueues; even failed exploitation reliably crashes or hangs the affected controller path."
            }
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        "dateUpdated": "2026-08-17T05:45:38.299Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/48c7ad6afcc58c2cda11fed39791708103b6a644"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74302",
    "datePublished": "2026-08-15T05:58:04.638Z",
    "dateReserved": "2026-08-15T05:44:03.882Z",
    "dateUpdated": "2026-08-17T05:45:38.299Z",
    "state": "PUBLISHED"
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If a timeout fires\\nduring device teardown, the callback dereferences freed memory\\n(including the hdev-\u003ereset function pointer), leading to a\\nuse-after-free.\\n\\nAdd disable_delayed_work_sync() calls alongside the existing\\ndisable_work_sync() calls to ensure both timers are fully\\nquiesced before teardown proceeds.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/bluetooth/hci_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"0d151a103775dd9645c78c97f77d6e2a5298d913\",\"lessThan\":\"48c7ad6afcc58c2cda11fed39791708103b6a644\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0d151a103775dd9645c78c97f77d6e2a5298d913\",\"lessThan\":\"a0fd1086a57b982f8c24ae4ab165c2af39fe1735\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0d151a103775dd9645c78c97f77d6e2a5298d913\",\"lessThan\":\"672d52d9412252e61b8de8d773ccdf5a277cf540\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0d151a103775dd9645c78c97f77d6e2a5298d913\",\"lessThan\":\"5edcc018fa6e80b2c478454a4a8229c23d67c181\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"48542881997e17b49dc16b93fe910e0cfcf7a9f9\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9cfc84b1d464cc024286f42a090718f9067b80ed\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"ddeda6ca5f218b668b560d90fc31ae469adbfd92\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"d2ce562a5aff1dcd0c50d9808ea825ef90da909f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"96600c2e5ee8213dbab5df1617293d8e847bb4fa\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"d6cbce18370641a21dd889e8613d8153df15eb39\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3f939bd73fed12dddc2a32a76116c19ca47c7678\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"4.19.319\",\"lessThan\":\"4.20\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.4.281\",\"lessThan\":\"5.5\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.10.223\",\"lessThan\":\"5.11\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.15.164\",\"lessThan\":\"5.16\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.1.101\",\"lessThan\":\"6.2\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.6.42\",\"lessThan\":\"6.7\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"6.9.11\",\"lessThan\":\"6.10\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/bluetooth/hci_core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.10\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.10\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/48c7ad6afcc58c2cda11fed39791708103b6a644\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5edcc018fa6e80b2c478454a4a8229c23d67c181\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/672d52d9412252e61b8de8d773ccdf5a277cf540\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a0fd1086a57b982f8c24ae4ab165c2af39fe1735\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T16:22:37+00:00",
      "cve": "CVE-2026-74302",
      "id": "CVE-2026-74302",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_core: Fix UAF in hci_unregister_dev()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74302.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

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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.
  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.