CVE-2026-98735 (GCVE-0-2026-98735)
Vulnerability from cvelistv5
Published
2026-10-18 15:47
Modified
2026-10-30 12:39
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_core: Serialize ACL scheduling with channel deletion hci_chan_sent() selects a channel under RCU but drops the read lock before accessing chan->conn and returning the channel. The ACL and LE schedulers then use its packet queue and update its transmit counters without any protection against channel deletion. After TX selects a channel and releases RCU, a disconnect command timeout on the separate request workqueue can run hci_conn_failed() and l2cap_conn_del(). hci_chan_del() can then unlink the channel, complete synchronize_rcu(), purge its queue and free it before TX resumes. This causes use-after-free both in hci_chan_sent() and in its callers. KASAN reported: BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0 Workqueue: hci0 hci_tx_work Call Trace: hci_chan_sent+0x892/0x9b0 hci_tx_work+0x5e6/0xb70 Allocated by task 91: hci_chan_create+0xe3/0x350 l2cap_conn_add.part.0+0x12/0xa30 l2cap_chan_connect+0x110d/0x1b60 l2cap_sock_connect+0x310/0x530 Freed by task 99: hci_chan_del+0x11f/0x170 l2cap_conn_del+0x4f1/0x800 l2cap_connect_cfm+0x88c/0xd30 hci_conn_failed+0x150/0x250 hci_abort_conn_sync+0x3e3/0x800 hci_cmd_sync_run+0x7e/0xc0 hci_abort_conn+0x105/0x1f0 disconnect_sync+0x157/0x290 hci_cmd_sync_work+0x13c/0x290 Hold the existing device mutex across channel selection and transmission in both schedulers to serialize them with channel teardown. Keep timeout handling outside the critical sections because hci_link_tx_to() acquires the same mutex. This also permits the transmit path to sleep, unlike extending the RCU read-side critical section across packet submission.
References
Impacted products
Vendor Product Version
Linux Linux Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
Version: 3eff45eaf81780dad25c167bbaafa7d25ae407da
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/bluetooth/hci_core.c"
          ],
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          "vendor": "Linux",
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              "version": "0",
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              "version": "6.1.191",
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              "version": "6.6.160",
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              "version": "6.12.113",
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              "version": "7.2.10",
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            },
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              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: Serialize ACL scheduling with channel deletion\n\nhci_chan_sent() selects a channel under RCU but drops the read lock before\naccessing chan-\u003econn and returning the channel. The ACL and LE schedulers\nthen use its packet queue and update its transmit counters without any\nprotection against channel deletion.\n\nAfter TX selects a channel and releases RCU, a disconnect command timeout\non the separate request workqueue can run hci_conn_failed() and\nl2cap_conn_del(). hci_chan_del() can then unlink the channel, complete\nsynchronize_rcu(), purge its queue and free it before TX resumes. This\ncauses use-after-free both in hci_chan_sent() and in its callers.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in hci_chan_sent+0x892/0x9b0\n  Workqueue: hci0 hci_tx_work\n  Call Trace:\n   hci_chan_sent+0x892/0x9b0\n   hci_tx_work+0x5e6/0xb70\n  Allocated by task 91:\n   hci_chan_create+0xe3/0x350\n   l2cap_conn_add.part.0+0x12/0xa30\n   l2cap_chan_connect+0x110d/0x1b60\n   l2cap_sock_connect+0x310/0x530\n  Freed by task 99:\n   hci_chan_del+0x11f/0x170\n   l2cap_conn_del+0x4f1/0x800\n   l2cap_connect_cfm+0x88c/0xd30\n   hci_conn_failed+0x150/0x250\n   hci_abort_conn_sync+0x3e3/0x800\n   hci_cmd_sync_run+0x7e/0xc0\n   hci_abort_conn+0x105/0x1f0\n   disconnect_sync+0x157/0x290\n   hci_cmd_sync_work+0x13c/0x290\n\nHold the existing device mutex across channel selection and transmission\nin both schedulers to serialize them with channel teardown. Keep timeout\nhandling outside the critical sections because hci_link_tx_to() acquires\nthe same mutex. This also permits the transmit path to sleep, unlike\nextending the RCU read-side critical section across packet submission."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:39:11.976Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/126714c495bf31a5e71411b8e0b65a685bb5e58d"
        },
        {
          "url": "https://git.kernel.org/stable/c/7fbeda3dcd5f54e7429f4b5e2cfa7344b7e9b1c9"
        },
        {
          "url": "https://git.kernel.org/stable/c/74667f6eb7c12b65c56e02e0f527e4099db4ebfd"
        },
        {
          "url": "https://git.kernel.org/stable/c/780affacd92977fd9b819bdc4f26a6832cb27fda"
        },
        {
          "url": "https://git.kernel.org/stable/c/51f95ea451f25d7e3f048c0f438f04fa74688aae"
        },
        {
          "url": "https://git.kernel.org/stable/c/86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/4fda8f0abeea9929036446d89a476fb8298abcb0"
        },
        {
          "url": "https://git.kernel.org/stable/c/f4845ab191a4f686a5da481fbba90ed73bb693b0"
        }
      ],
      "title": "Bluetooth: hci_core: Serialize ACL scheduling with channel deletion",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98735",
    "datePublished": "2026-10-18T15:47:13.062Z",
    "dateReserved": "2026-09-25T10:25:14.367Z",
    "dateUpdated": "2026-10-30T12:39:11.976Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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