CVE-2026-98736 (GCVE-0-2026-98736)
Vulnerability from cvelistv5
Published
2026-10-18 15:47
Modified
2026-10-21 12:56
Severity ?
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.
References
Impacted products
Vendor Product Version
Linux Linux Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
Version: e07a06b4eb417f5271d33ce2240e93c62d98b7b4
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "70b55855eecb428d446344d827bda8725ce8b312",
              "status": "affected",
              "version": "e07a06b4eb417f5271d33ce2240e93c62d98b7b4",
              "versionType": "git"
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              "versionType": "git"
            },
            {
              "lessThan": "024e05f73a4c1263d031614bc36700ec135eecb4",
              "status": "affected",
              "version": "e07a06b4eb417f5271d33ce2240e93c62d98b7b4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_conn.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
              "lessThan": "6.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.113",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.56",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.10",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:56:12.287Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/70b55855eecb428d446344d827bda8725ce8b312"
        },
        {
          "url": "https://git.kernel.org/stable/c/1239ef0fa809b5952fca679db3faa3e1c00e1dac"
        },
        {
          "url": "https://git.kernel.org/stable/c/cabd58d9bb66d49d481f762ce986173db397435d"
        },
        {
          "url": "https://git.kernel.org/stable/c/93a737e4e042f59673cd580d35214f278d7b757d"
        },
        {
          "url": "https://git.kernel.org/stable/c/024e05f73a4c1263d031614bc36700ec135eecb4"
        }
      ],
      "title": "Bluetooth: hci_conn: Lock parent access during enhanced SCO setup",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98736",
    "datePublished": "2026-10-18T15:47:14.076Z",
    "dateReserved": "2026-09-25T10:25:14.367Z",
    "dateUpdated": "2026-10-21T12:56:12.287Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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