{"id":"CVE-2026-99011","title":"Bluetooth: SCO: serialise sco_conn lifetime against sco_recv_scodata()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: SCO: serialise sco_conn lifetime against sco_recv_scodata()\n\nsco_recv_scodata() upgrades the weak hcon->sco_data back-pointer to a\nstrong reference under hde…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < b108ea7ebba147465f4158d8133f0e8f013762ed","Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < 8a98d58f6cfe70d51138cd9ce894e72671d95f8a","Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < 816fb1590a4c8cf8d05cd076057616be02e276f0","Linux 6.13"],"published":"2026-10-23","updated":"2026-10-24","sourceUpdated":"2026-10-24T14:09:59.382Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99011","references":[{"url":"https://git.kernel.org/stable/c/b108ea7ebba147465f4158d8133f0e8f013762ed"},{"url":"https://git.kernel.org/stable/c/8a98d58f6cfe70d51138cd9ce894e72671d95f8a"},{"url":"https://git.kernel.org/stable/c/816fb1590a4c8cf8d05cd076057616be02e276f0"}],"tags":["cve.org"],"epss":0.00206,"epssPercentile":0.1016,"ingestedAt":"2026-10-23T13:24:55.538Z","slug":"CVE-2026-99011","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: SCO: serialise sco_conn lifetime against sco_recv_scodata()\n\nsco_recv_scodata() upgrades the weak hcon->sco_data back-pointer to a\nstrong reference under hdev->lock:\n\n    hci_dev_lock(hdev);\n    hcon = hci_conn_hash_lookup_handle(hdev, handle);\n    ...\n    conn = sco_conn_hold_unless_zero(hcon->sco_data);\n    hci_dev_unlock(hdev);\n\nbut the pointer is cleared from the other side without that lock. When\nthe last sco_conn reference is dropped, sco_conn_free() ran\n\n    conn->hcon->sco_data = NULL;\n\nwith no hdev->lock held, so the RX path could read hcon->sco_data and\ncall kref_get_unless_zero() on an sco_conn that was concurrently freed:\n\n    BUG: KASAN: slab-use-after-free in sco_conn_hold_unless_zero+0xbe/0x160\n    Write of size 4 by task kworker/u17:0\n    Workqueue: hci0 hci_rx_work\n    Call Trace:\n     sco_conn_hold_unless_zero+0xbe/0x160\n     sco_recv_scodata+0x13f/0x490\n     hci_rx_work+0x3af/0x730\n\nkref_get_unless_zero() only guards against a zero refcount, not against\nthe backing memory already being freed.\n\nGive hcon->sco_data an actual reference on the sco_conn it points to, so\nthe object cannot be freed while the pointer is still installed, and only\nclear and drop it from sco_conn_del(), which runs under hdev->lock (its\ncallers, sco_connect_cfm() and sco_disconn_cfm(), hold it). The reader in\nsco_recv_scodata() also takes hdev->lock, so the store and the read are\nnow serialised: the RX path either observes NULL or a reference that is\nguaranteed to stay valid until it drops its own.\n\nsco_conn_add() no longer hands its kref_init() reference to the caller as\nthe connection's only reference; that initial reference is the one owned\nby hcon->sco_data, and callers get their own via sco_conn_hold().\n\nBecause the sco_conn can now outlive the socket (the association keeps it\nalive until the link goes down), the hci_conn can no longer be dropped\nfrom sco_conn_free() without regressing socket close: closing a connected\nSCO socket must still tear the link down. Move hci_conn ownership to the\nsocket instead: __sco_chan_add() takes an hci_conn reference and it is\nreleased from sco_chan_del() and sco_sock_destruct(), exactly once. The\nsco_conn no longer owns an hci_conn reference, so sco_conn_add() stops\nconsuming one and sco_connect() drops the hci_connect_sco() reference on\nevery path; sco_connect_cfm() no longer needs its hci_conn_hold() dance.\n\n## Affected\n\n- `Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < b108ea7ebba147465f4158d8133f0e8f013762ed`\n- `Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < 8a98d58f6cfe70d51138cd9ce894e72671d95f8a`\n- `Linux >= e6720779ae612a14ac4ba7fe4fd5b27d900d932c < 816fb1590a4c8cf8d05cd076057616be02e276f0`\n- `Linux 6.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":228864,"id":"CVE-2026-99011","ts":1792854094760,"field":"cvss","old":null,"new":"7.1"},{"seq":228863,"id":"CVE-2026-99011","ts":1792854094760,"field":"severity","old":"none","new":"high"}]}