CVE-2026-98736 (GCVE-0-2026-98736)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:47 – Updated: 2026-10-30 12:39
VLAI
Title
Bluetooth: hci_conn: Lock parent access during enhanced SCO setup
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: Lock parent access during enhanced SCO setup Bluetooth: hci_conn: Lock parent access during enhanced SCO setup hci_enhanced_setup_sync() runs on the request workqueue without the hci_dev_lock held by its caller when setup was queued. Its CVSD capability check and find_next_esco_param() dereference conn->parent while the receive workqueue can unlink and release that parent. The following interleaving can cause a use-after-free: hci_enhanced_setup_sync() hci_disconn_complete_evt() load conn->parent hci_dev_lock() hci_conn_del(ACL parent) unlink SCO child drop link's parent reference clear child->parent release ACL parent bt_link_release() kfree(parent) hci_dev_unlock() read parent->features[0][3] The reference held for the queued SCO child does not keep its ACL parent alive after unlinking. Commit 42de40abe25d ("Bluetooth: hci_conn: fix the SCO setup context lifetime") protects the child stored in the queued context, but leaves these parent accesses unprotected. With a 40 ms diagnostic delay after loading conn->parent, an instrumented kernel based on fd179f8a05be, which already contains 42de40abe25d, BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0 Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93 Call Trace: hci_enhanced_setup_sync+0xda5/0xdf0 hci_cmd_sync_work+0x13c/0x290 process_one_work+0x6b4/0x10e0 Allocated by task 92: __hci_conn_add+0x304/0x1df0 hci_connect_acl+0x349/0x3e0 hci_connect_sco+0x3b/0x9a0 sco_sock_connect+0x475/0xca0 Freed by task 94: kfree+0x121/0x3c0 bt_link_release+0x79/0xa0 device_release+0xc8/0x240 kobject_put+0x14d/0x280 hci_conn_del+0x524/0xe30 hci_disconn_complete_evt+0x403/0x8c0 hci_event_packet+0x71b/0xb20 hci_rx_work+0x293/0x730 The accessed address is 71 bytes into the freed ACL parent, at its features[0][3] byte; the queued SCO child is a different object. The diagnostic preserves the loaded parent across the delay, matching the unmodified compiled capability check, and does not change the parent references or teardown path. Hold hci_dev_lock() across the codec switch, including every call to find_next_esco_param(), and release it on all selection errors. Keep configure_datapath_sync() outside the critical section because it waits for HCI events. Preserve parameter selection and existing return values.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7018 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 48bf3b94c7331e11eaa6c89adc054a7bc7c0382e (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 70b55855eecb428d446344d827bda8725ce8b312 (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 1239ef0fa809b5952fca679db3faa3e1c00e1dac (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < cabd58d9bb66d49d481f762ce986173db397435d (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 93a737e4e042f59673cd580d35214f278d7b757d (git)
Affected: e07a06b4eb417f5271d33ce2240e93c62d98b7b4 , < 024e05f73a4c1263d031614bc36700ec135eecb4 (git)
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Linux Linux Affected: 6.1
Unaffected: 0 , < 6.1 (semver)
Unaffected: 6.1.191 , ≤ 6.1.* (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.113 , ≤ 6.12.* (semver)
Unaffected: 6.18.56 , ≤ 6.18.* (semver)
Unaffected: 7.2.10 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nhci_enhanced_setup_sync() runs on the request workqueue without the\nhci_dev_lock held by its caller when setup was queued. Its CVSD\ncapability check and find_next_esco_param() dereference conn-\u003eparent\nwhile the receive workqueue can unlink and release that parent.\n\nThe following interleaving can cause a use-after-free:\n\n  hci_enhanced_setup_sync()       hci_disconn_complete_evt()\n  load conn-\u003eparent\n                                 hci_dev_lock()\n                                 hci_conn_del(ACL parent)\n                                   unlink SCO child\n                                   drop link\u0027s parent reference\n                                   clear child-\u003eparent\n                                   release ACL parent\n                                     bt_link_release()\n                                       kfree(parent)\n                                 hci_dev_unlock()\n  read parent-\u003efeatures[0][3]\n\nThe reference held for the queued SCO child does not keep its ACL parent\nalive after unlinking. Commit 42de40abe25d (\"Bluetooth: hci_conn: fix the\nSCO setup context lifetime\") protects the child stored in the queued\ncontext, but leaves these parent accesses unprotected.\n\nWith a 40 ms diagnostic delay after loading conn-\u003eparent, an instrumented\nkernel based on fd179f8a05be, which already contains 42de40abe25d,\n\n  BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0\n  Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93\n  Call Trace:\n   hci_enhanced_setup_sync+0xda5/0xdf0\n   hci_cmd_sync_work+0x13c/0x290\n   process_one_work+0x6b4/0x10e0\n\n  Allocated by task 92:\n   __hci_conn_add+0x304/0x1df0\n   hci_connect_acl+0x349/0x3e0\n   hci_connect_sco+0x3b/0x9a0\n   sco_sock_connect+0x475/0xca0\n\n  Freed by task 94:\n   kfree+0x121/0x3c0\n   bt_link_release+0x79/0xa0\n   device_release+0xc8/0x240\n   kobject_put+0x14d/0x280\n   hci_conn_del+0x524/0xe30\n   hci_disconn_complete_evt+0x403/0x8c0\n   hci_event_packet+0x71b/0xb20\n   hci_rx_work+0x293/0x730\n\nThe accessed address is 71 bytes into the freed ACL parent, at its\nfeatures[0][3] byte; the queued SCO child is a different object. The\ndiagnostic preserves the loaded parent across the delay, matching the\nunmodified compiled capability check, and does not change the parent\nreferences or teardown path.\n\nHold hci_dev_lock() across the codec switch, including every call to\nfind_next_esco_param(), and release it on all selection errors. Keep\nconfigure_datapath_sync() outside the critical section because it waits\nfor HCI events. Preserve parameter selection and existing return values."
        }
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        "dateUpdated": "2026-10-30T12:39:13.042Z",
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      "references": [
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          "url": "https://git.kernel.org/stable/c/48bf3b94c7331e11eaa6c89adc054a7bc7c0382e"
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        {
          "url": "https://git.kernel.org/stable/c/70b55855eecb428d446344d827bda8725ce8b312"
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        },
        {
          "url": "https://git.kernel.org/stable/c/024e05f73a4c1263d031614bc36700ec135eecb4"
        }
      ],
      "title": "Bluetooth: hci_conn: Lock parent access during enhanced SCO setup",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98736",
    "datePublished": "2026-10-18T15:47:14.076Z",
    "dateReserved": "2026-09-25T10:25:14.367Z",
    "dateUpdated": "2026-10-30T12:39:13.042Z",
    "state": "PUBLISHED"
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      "epss": "0.00172",
      "percentile": "0.0661"
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      "cve": "CVE-2026-98736",
      "id": "msrc_CVE-2026-98736",
      "initial_release_date": "2026-10-20T01:07:30.000Z",
      "product_status:known_affected": "1",
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      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "Bluetooth: hci_conn: Lock parent access during enhanced SCO setup",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-98736.json",
      "version": "3"
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        "affected": [
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                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nhci_enhanced_setup_sync() runs on the request workqueue without the\nhci_dev_lock held by its caller when setup was queued. Its CVSD\ncapability check and find_next_esco_param() dereference conn-\u003eparent\nwhile the receive workqueue can unlink and release that parent.\n\nThe following interleaving can cause a use-after-free:\n\n  hci_enhanced_setup_sync()       hci_disconn_complete_evt()\n  load conn-\u003eparent\n                                 hci_dev_lock()\n                                 hci_conn_del(ACL parent)\n                                   unlink SCO child\n                                   drop link\u0027s parent reference\n                                   clear child-\u003eparent\n                                   release ACL parent\n                                     bt_link_release()\n                                       kfree(parent)\n                                 hci_dev_unlock()\n  read parent-\u003efeatures[0][3]\n\nThe reference held for the queued SCO child does not keep its ACL parent\nalive after unlinking. Commit 42de40abe25d (\"Bluetooth: hci_conn: fix the\nSCO setup context lifetime\") protects the child stored in the queued\ncontext, but leaves these parent accesses unprotected.\n\nWith a 40 ms diagnostic delay after loading conn-\u003eparent, an instrumented\nkernel based on fd179f8a05be, which already contains 42de40abe25d,\n\n  BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0\n  Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93\n  Call Trace:\n   hci_enhanced_setup_sync+0xda5/0xdf0\n   hci_cmd_sync_work+0x13c/0x290\n   process_one_work+0x6b4/0x10e0\n\n  Allocated by task 92:\n   __hci_conn_add+0x304/0x1df0\n   hci_connect_acl+0x349/0x3e0\n   hci_connect_sco+0x3b/0x9a0\n   sco_sock_connect+0x475/0xca0\n\n  Freed by task 94:\n   kfree+0x121/0x3c0\n   bt_link_release+0x79/0xa0\n   device_release+0xc8/0x240\n   kobject_put+0x14d/0x280\n   hci_conn_del+0x524/0xe30\n   hci_disconn_complete_evt+0x403/0x8c0\n   hci_event_packet+0x71b/0xb20\n   hci_rx_work+0x293/0x730\n\nThe accessed address is 71 bytes into the freed ACL parent, at its\nfeatures[0][3] byte; the queued SCO child is a different object. The\ndiagnostic preserves the loaded parent across the delay, matching the\nunmodified compiled capability check, and does not change the parent\nreferences or teardown path.\n\nHold hci_dev_lock() across the codec switch, including every call to\nfind_next_esco_param(), and release it on all selection errors. Keep\nconfigure_datapath_sync() outside the critical section because it waits\nfor HCI events. Preserve parameter selection and existing return values."
          }
        ],
        "id": "CVE-2026-98736",
        "lastModified": "2026-10-30T13:21:22.400",
        "metrics": {},
        "published": "2026-10-18T16:17:27.237",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/024e05f73a4c1263d031614bc36700ec135eecb4"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/1239ef0fa809b5952fca679db3faa3e1c00e1dac"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/48bf3b94c7331e11eaa6c89adc054a7bc7c0382e"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/70b55855eecb428d446344d827bda8725ce8b312"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/93a737e4e042f59673cd580d35214f278d7b757d"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/cabd58d9bb66d49d481f762ce986173db397435d"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-10-23T01:35:32+00:00",
      "cve": "CVE-2026-98736",
      "id": "CVE-2026-98736",
      "initial_release_date": "2026-10-18T00:00:00+00:00",
      "product_status:known_affected": "199",
      "product_status:known_not_affected": "79",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Bluetooth: hci_conn: Lock parent access during enhanced SCO setup",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98736.json",
      "version": "3"
    }
  }
}



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Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.