Vulnerability-Lookup

CVE-2026-46275 (GCVE-0-2026-46275)

Vulnerability from cvelistv5 – Published: 2026-06-08 14:30 – Updated: 2026-06-14 18:05

Title

Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

Summary

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer Dereference (NPD) conditions were observed in the lifecycle management of hci_uart. The primary issue arises because the workqueues (init_ready and write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY flag is set during TTY close. If a hangup occurs before setup completes, hci_uart_tty_close() skips the teardown of these workqueues and proceeds to free the `hu` struct. When the scheduled work executes later, it blindly dereferences the freed `hu` struct. Furthermore, several data races and UAFs were identified in the teardown sequence: 1. Calling hci_uart_flush() from hci_uart_close() without effectively disabling write_work causes a race condition where both can concurrently double-free hu->tx_skb. This happens because protocol timers can concurrently invoke hci_uart_tx_wakeup() and requeue write_work. 2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF when vendor specific protocol close callbacks dereference hu->hdev. 3. In the initialization error paths, failing to take the proto_lock write lock before clearing PROTO_READY leads to races with active readers. Additionally, hci_uart_tty_receive() accesses hu->hdev outside the read lock, leading to UAFs if the initialization error path frees hdev concurrently. Fix these synchronization and lifecycle issues by: 1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first, followed immediately by a cancel_work_sync(&hu->write_work). Clearing the flag locks out concurrent protocol timers from successfully invoking hci_uart_tx_wakeup(), effectively rendering the cancellation permanent and preventing the tx_skb double-free. 2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip hu->proto->flush(). This is perfectly safe in the tty_close path because hu->proto->close() executes shortly after, which intrinsically purges all protocol SKB queues and tears down the state. 3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev) across all close and error paths to prevent vendor-level UAFs. 4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive() inside the proto_lock read-side critical section to safely synchronize with device unregistration. 5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely flush the workqueue before hci_uart_flush() is invoked via the HCI core. 6. Utilizing cancel_work_sync() instead of disable_work_sync() across all paths to prevent permanently breaking user-space retry capabilities.

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

References

8 references

URL	Tags
https://git.kernel.org/stable/c/78aad93e938f013d9…
https://git.kernel.org/stable/c/e2d19969c8d9198ec…
https://git.kernel.org/stable/c/c85cff648a2bc9232…
https://git.kernel.org/stable/c/9d20d48be2c4a071f…
https://git.kernel.org/stable/c/81c7a3c22a0f2808c…
https://git.kernel.org/stable/c/192cb0f1ca706d9a1…
https://git.kernel.org/stable/c/7338031946bd06f6d…
https://git.kernel.org/stable/c/c1bb9336ae6b54a5f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < 78aad93e938f013d9272fe0ee168f27883afa95c (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < e2d19969c8d9198ecc3090bcd5312ecd503a3339 (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < c85cff648a2bc92322912db5f1727ad05afae7b6 (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < 9d20d48be2c4a071fb015eb09bda2cecd25daf34 (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < 81c7a3c22a0f2808cf4ae0b4908f59763b23606d (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < 192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894 (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < 7338031946bd06f6dff149e67b60c4cd083bfea8 (git) Affected: 3b799254cf6f481460719023d7a18f46651e5e7f , < c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b (git) Affected: cd27019bc149f20f12ebec943c2b4c775745a5a0 (git) Affected: aea63181b6fcb6b9ccde1ada9ea51be19c4015af (git) Affected: 0d234d1135dcd8876de0576dac68efd0a87eef87 (git) Affected: 3fe978892ab46efc2f3830d9abc015eff72caaf9 (git) Affected: 0d987e14bebaf0f67ee7dbefaf6165c62cd1d27f (git) Affected: 4.14.203 , < 4.15 (semver) Affected: 4.19.153 , < 4.20 (semver) Affected: 5.4.73 , < 5.5 (semver) Affected: 5.8.17 , < 5.9 (semver) Affected: 5.9.2 , < 5.10 (semver)
Linux	Linux	Affected: 5.10 Unaffected: 0 , < 5.10 (semver) Unaffected: 5.10.258 , ≤ 5.10.* (semver) Unaffected: 5.15.209 , ≤ 5.15.* (semver) Unaffected: 6.1.175 , ≤ 6.1.* (semver) Unaffected: 6.6.142 , ≤ 6.6.* (semver) Unaffected: 6.12.92 , ≤ 6.12.* (semver) Unaffected: 6.18.34 , ≤ 6.18.* (semver) Unaffected: 7.0.11 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_uart: fix UAFs and race conditions in close and init paths\n\nVulnerabilities leading to Use-After-Free (UAF) and Null Pointer\nDereference (NPD) conditions were observed in the lifecycle management\nof hci_uart.\n\nThe primary issue arises because the workqueues (init_ready and\nwrite_work) are only flushed/cancelled if the HCI_UART_PROTO_READY\nflag is set during TTY close. If a hangup occurs before setup completes,\nhci_uart_tty_close() skips the teardown of these workqueues and\nproceeds to free the `hu` struct. When the scheduled work executes\nlater, it blindly dereferences the freed `hu` struct.\n\nFurthermore, several data races and UAFs were identified in the teardown\nsequence:\n1. Calling hci_uart_flush() from hci_uart_close() without effectively\n   disabling write_work causes a race condition where both can concurrently\n   double-free hu-\u003etx_skb. This happens because protocol timers can\n   concurrently invoke hci_uart_tx_wakeup() and requeue write_work.\n2. Calling hci_free_dev(hdev) before hu-\u003eproto-\u003eclose(hu) causes a UAF\n   when vendor specific protocol close callbacks dereference hu-\u003ehdev.\n3. In the initialization error paths, failing to take the proto_lock\n   write lock before clearing PROTO_READY leads to races with active\n   readers. Additionally, hci_uart_tty_receive() accesses hu-\u003ehdev\n   outside the read lock, leading to UAFs if the initialization error\n   path frees hdev concurrently.\n\nFix these synchronization and lifecycle issues by:\n1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,\n   followed immediately by a cancel_work_sync(\u0026hu-\u003ewrite_work). Clearing\n   the flag locks out concurrent protocol timers from successfully invoking\n   hci_uart_tx_wakeup(), effectively rendering the cancellation permanent\n   and preventing the tx_skb double-free.\n2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip\n   hu-\u003eproto-\u003eflush(). This is perfectly safe in the tty_close path\n   because hu-\u003eproto-\u003eclose() executes shortly after, which intrinsically\n   purges all protocol SKB queues and tears down the state.\n3. Relocating hu-\u003eproto-\u003eclose(hu) strictly prior to hci_free_dev(hdev)\n   across all close and error paths to prevent vendor-level UAFs.\n4. Moving the hdev-\u003estat.byte_rx increment in hci_uart_tty_receive()\n   inside the proto_lock read-side critical section to safely synchronize\n   with device unregistration.\n5. Adding cancel_work_sync(\u0026hu-\u003ewrite_work) to hci_uart_close() to safely\n   flush the workqueue before hci_uart_flush() is invoked via the HCI core.\n6. Utilizing cancel_work_sync() instead of disable_work_sync() across\n   all paths to prevent permanently breaking user-space retry capabilities."
        }
      ],
      "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"
          }
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T18:05:39.086Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c"
        },
        {
          "url": "https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339"
        },
        {
          "url": "https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6"
        },
        {
          "url": "https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34"
        },
        {
          "url": "https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d"
        },
        {
          "url": "https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894"
        },
        {
          "url": "https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8"
        },
        {
          "url": "https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b"
        }
      ],
      "title": "Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46275",
    "datePublished": "2026-06-08T14:30:54.232Z",
    "dateReserved": "2026-05-13T15:03:33.109Z",
    "dateUpdated": "2026-06-14T18:05:39.086Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-46275",
      "date": "2026-06-16",
      "epss": "0.00204",
      "percentile": "0.10346"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-46275\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-06-08T16:16:40.863\",\"lastModified\":\"2026-06-14T06:16:22.753\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nBluetooth: hci_uart: fix UAFs and race conditions in close and init paths\\n\\nVulnerabilities leading to Use-After-Free (UAF) and Null Pointer\\nDereference (NPD) conditions were observed in the lifecycle management\\nof hci_uart.\\n\\nThe primary issue arises because the workqueues (init_ready and\\nwrite_work) are only flushed/cancelled if the HCI_UART_PROTO_READY\\nflag is set during TTY close. If a hangup occurs before setup completes,\\nhci_uart_tty_close() skips the teardown of these workqueues and\\nproceeds to free the `hu` struct. When the scheduled work executes\\nlater, it blindly dereferences the freed `hu` struct.\\n\\nFurthermore, several data races and UAFs were identified in the teardown\\nsequence:\\n1. Calling hci_uart_flush() from hci_uart_close() without effectively\\n   disabling write_work causes a race condition where both can concurrently\\n   double-free hu-\u003etx_skb. This happens because protocol timers can\\n   concurrently invoke hci_uart_tx_wakeup() and requeue write_work.\\n2. Calling hci_free_dev(hdev) before hu-\u003eproto-\u003eclose(hu) causes a UAF\\n   when vendor specific protocol close callbacks dereference hu-\u003ehdev.\\n3. In the initialization error paths, failing to take the proto_lock\\n   write lock before clearing PROTO_READY leads to races with active\\n   readers. Additionally, hci_uart_tty_receive() accesses hu-\u003ehdev\\n   outside the read lock, leading to UAFs if the initialization error\\n   path frees hdev concurrently.\\n\\nFix these synchronization and lifecycle issues by:\\n1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,\\n   followed immediately by a cancel_work_sync(\u0026hu-\u003ewrite_work). Clearing\\n   the flag locks out concurrent protocol timers from successfully invoking\\n   hci_uart_tx_wakeup(), effectively rendering the cancellation permanent\\n   and preventing the tx_skb double-free.\\n2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip\\n   hu-\u003eproto-\u003eflush(). This is perfectly safe in the tty_close path\\n   because hu-\u003eproto-\u003eclose() executes shortly after, which intrinsically\\n   purges all protocol SKB queues and tears down the state.\\n3. Relocating hu-\u003eproto-\u003eclose(hu) strictly prior to hci_free_dev(hdev)\\n   across all close and error paths to prevent vendor-level UAFs.\\n4. Moving the hdev-\u003estat.byte_rx increment in hci_uart_tty_receive()\\n   inside the proto_lock read-side critical section to safely synchronize\\n   with device unregistration.\\n5. Adding cancel_work_sync(\u0026hu-\u003ewrite_work) to hci_uart_close() to safely\\n   flush the workqueue before hci_uart_flush() is invoked via the HCI core.\\n6. Utilizing cancel_work_sync() instead of disable_work_sync() across\\n   all paths to prevent permanently breaking user-space retry capabilities.\"}],\"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/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2026-46275

Vulnerability from fkie_nvd - Published: 2026-06-08 16:16 - Updated: 2026-06-14 06:16

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_uart: fix UAFs and race conditions in close and init paths\n\nVulnerabilities leading to Use-After-Free (UAF) and Null Pointer\nDereference (NPD) conditions were observed in the lifecycle management\nof hci_uart.\n\nThe primary issue arises because the workqueues (init_ready and\nwrite_work) are only flushed/cancelled if the HCI_UART_PROTO_READY\nflag is set during TTY close. If a hangup occurs before setup completes,\nhci_uart_tty_close() skips the teardown of these workqueues and\nproceeds to free the `hu` struct. When the scheduled work executes\nlater, it blindly dereferences the freed `hu` struct.\n\nFurthermore, several data races and UAFs were identified in the teardown\nsequence:\n1. Calling hci_uart_flush() from hci_uart_close() without effectively\n   disabling write_work causes a race condition where both can concurrently\n   double-free hu-\u003etx_skb. This happens because protocol timers can\n   concurrently invoke hci_uart_tx_wakeup() and requeue write_work.\n2. Calling hci_free_dev(hdev) before hu-\u003eproto-\u003eclose(hu) causes a UAF\n   when vendor specific protocol close callbacks dereference hu-\u003ehdev.\n3. In the initialization error paths, failing to take the proto_lock\n   write lock before clearing PROTO_READY leads to races with active\n   readers. Additionally, hci_uart_tty_receive() accesses hu-\u003ehdev\n   outside the read lock, leading to UAFs if the initialization error\n   path frees hdev concurrently.\n\nFix these synchronization and lifecycle issues by:\n1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,\n   followed immediately by a cancel_work_sync(\u0026hu-\u003ewrite_work). Clearing\n   the flag locks out concurrent protocol timers from successfully invoking\n   hci_uart_tx_wakeup(), effectively rendering the cancellation permanent\n   and preventing the tx_skb double-free.\n2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip\n   hu-\u003eproto-\u003eflush(). This is perfectly safe in the tty_close path\n   because hu-\u003eproto-\u003eclose() executes shortly after, which intrinsically\n   purges all protocol SKB queues and tears down the state.\n3. Relocating hu-\u003eproto-\u003eclose(hu) strictly prior to hci_free_dev(hdev)\n   across all close and error paths to prevent vendor-level UAFs.\n4. Moving the hdev-\u003estat.byte_rx increment in hci_uart_tty_receive()\n   inside the proto_lock read-side critical section to safely synchronize\n   with device unregistration.\n5. Adding cancel_work_sync(\u0026hu-\u003ewrite_work) to hci_uart_close() to safely\n   flush the workqueue before hci_uart_flush() is invoked via the HCI core.\n6. Utilizing cancel_work_sync() instead of disable_work_sync() across\n   all paths to prevent permanently breaking user-space retry capabilities."
    }
  ],
  "id": "CVE-2026-46275",
  "lastModified": "2026-06-14T06:16:22.753",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-08T16:16:40.863",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-MPVF-W98G-3C74

Vulnerability from github – Published: 2026-06-08 18:31 – Updated: 2026-06-14 06:30

Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

Vulnerabilities leading to Use-After-Free (UAF) and Null Pointer Dereference (NPD) conditions were observed in the lifecycle management of hci_uart.

The primary issue arises because the workqueues (init_ready and write_work) are only flushed/cancelled if the HCI_UART_PROTO_READY flag is set during TTY close. If a hangup occurs before setup completes, hci_uart_tty_close() skips the teardown of these workqueues and proceeds to free the hu struct. When the scheduled work executes later, it blindly dereferences the freed hu struct.

Furthermore, several data races and UAFs were identified in the teardown sequence: 1. Calling hci_uart_flush() from hci_uart_close() without effectively disabling write_work causes a race condition where both can concurrently double-free hu->tx_skb. This happens because protocol timers can concurrently invoke hci_uart_tx_wakeup() and requeue write_work. 2. Calling hci_free_dev(hdev) before hu->proto->close(hu) causes a UAF when vendor specific protocol close callbacks dereference hu->hdev. 3. In the initialization error paths, failing to take the proto_lock write lock before clearing PROTO_READY leads to races with active readers. Additionally, hci_uart_tty_receive() accesses hu->hdev outside the read lock, leading to UAFs if the initialization error path frees hdev concurrently.

Fix these synchronization and lifecycle issues by: 1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first, followed immediately by a cancel_work_sync(&hu->write_work). Clearing the flag locks out concurrent protocol timers from successfully invoking hci_uart_tx_wakeup(), effectively rendering the cancellation permanent and preventing the tx_skb double-free. 2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip hu->proto->flush(). This is perfectly safe in the tty_close path because hu->proto->close() executes shortly after, which intrinsically purges all protocol SKB queues and tears down the state. 3. Relocating hu->proto->close(hu) strictly prior to hci_free_dev(hdev) across all close and error paths to prevent vendor-level UAFs. 4. Moving the hdev->stat.byte_rx increment in hci_uart_tty_receive() inside the proto_lock read-side critical section to safely synchronize with device unregistration. 5. Adding cancel_work_sync(&hu->write_work) to hci_uart_close() to safely flush the workqueue before hci_uart_flush() is invoked via the HCI core. 6. Utilizing cancel_work_sync() instead of disable_work_sync() across all paths to prevent permanently breaking user-space retry capabilities.

Severity

7.8 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-46275"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-08T16:16:40Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_uart: fix UAFs and race conditions in close and init paths\n\nVulnerabilities leading to Use-After-Free (UAF) and Null Pointer\nDereference (NPD) conditions were observed in the lifecycle management\nof hci_uart.\n\nThe primary issue arises because the workqueues (init_ready and\nwrite_work) are only flushed/cancelled if the HCI_UART_PROTO_READY\nflag is set during TTY close. If a hangup occurs before setup completes,\nhci_uart_tty_close() skips the teardown of these workqueues and\nproceeds to free the `hu` struct. When the scheduled work executes\nlater, it blindly dereferences the freed `hu` struct.\n\nFurthermore, several data races and UAFs were identified in the teardown\nsequence:\n1. Calling hci_uart_flush() from hci_uart_close() without effectively\n   disabling write_work causes a race condition where both can concurrently\n   double-free hu-\u003etx_skb. This happens because protocol timers can\n   concurrently invoke hci_uart_tx_wakeup() and requeue write_work.\n2. Calling hci_free_dev(hdev) before hu-\u003eproto-\u003eclose(hu) causes a UAF\n   when vendor specific protocol close callbacks dereference hu-\u003ehdev.\n3. In the initialization error paths, failing to take the proto_lock\n   write lock before clearing PROTO_READY leads to races with active\n   readers. Additionally, hci_uart_tty_receive() accesses hu-\u003ehdev\n   outside the read lock, leading to UAFs if the initialization error\n   path frees hdev concurrently.\n\nFix these synchronization and lifecycle issues by:\n1. Re-ordering hci_uart_tty_close() to clear HCI_UART_PROTO_READY first,\n   followed immediately by a cancel_work_sync(\u0026hu-\u003ewrite_work). Clearing\n   the flag locks out concurrent protocol timers from successfully invoking\n   hci_uart_tx_wakeup(), effectively rendering the cancellation permanent\n   and preventing the tx_skb double-free.\n2. Note: Clearing PROTO_READY early causes hci_uart_close() to skip\n   hu-\u003eproto-\u003eflush(). This is perfectly safe in the tty_close path\n   because hu-\u003eproto-\u003eclose() executes shortly after, which intrinsically\n   purges all protocol SKB queues and tears down the state.\n3. Relocating hu-\u003eproto-\u003eclose(hu) strictly prior to hci_free_dev(hdev)\n   across all close and error paths to prevent vendor-level UAFs.\n4. Moving the hdev-\u003estat.byte_rx increment in hci_uart_tty_receive()\n   inside the proto_lock read-side critical section to safely synchronize\n   with device unregistration.\n5. Adding cancel_work_sync(\u0026hu-\u003ewrite_work) to hci_uart_close() to safely\n   flush the workqueue before hci_uart_flush() is invoked via the HCI core.\n6. Utilizing cancel_work_sync() instead of disable_work_sync() across\n   all paths to prevent permanently breaking user-space retry capabilities.",
  "id": "GHSA-mpvf-w98g-3c74",
  "modified": "2026-06-14T06:30:23Z",
  "published": "2026-06-08T18:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46275"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/192cb0f1ca706d9a1bc36ae0ad5f666d1e4fd894"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7338031946bd06f6dff149e67b60c4cd083bfea8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/78aad93e938f013d9272fe0ee168f27883afa95c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81c7a3c22a0f2808cf4ae0b4908f59763b23606d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9d20d48be2c4a071fb015eb09bda2cecd25daf34"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c1bb9336ae6b54a5f6a353c4bd4ed9a4307e429b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c85cff648a2bc92322912db5f1727ad05afae7b6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e2d19969c8d9198ecc3090bcd5312ecd503a3339"
    }
  ],
  "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"
    }
  ]
}

MSRC_CVE-2026-46275

Vulnerability from csaf_microsoft - Published: 2026-06-02 00:00 - Updated: 2026-06-10 01:03

Summary

Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-46275

Affected products

Known affected 1 product

Product	Identifier	Version	Remediation
Unresolved product id: 17084-1		—	None Available

References

4 references

URL	Category
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-46275 Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-46275.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths",
    "tracking": {
      "current_release_date": "2026-06-10T01:03:52.000Z",
      "generator": {
        "date": "2026-06-10T07:02:18.586Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-46275",
      "initial_release_date": "2026-06-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2026-06-10T01:03:52.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "azl3 kernel 0:6.6.139.1-1.azl3",
                "product": {
                  "name": "azl3 kernel 0:6.6.139.1-1.azl3",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.139.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-46275",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-46275 Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-46275.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-06-10T01:03:52.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-1"
          ]
        }
      ],
      "title": "Bluetooth: hci_uart: fix UAFs and race conditions in close and init paths"
    }
  ]
}

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.

Action not permitted

CVE-2026-46275 (GCVE-0-2026-46275)

FKIE_CVE-2026-46275

GHSA-MPVF-W98G-3C74

MSRC_CVE-2026-46275

Tags

Sightings

Nomenclature