{"schema_version":"1.9.0","id":"CVE-2026-63944","published":"2026-07-19T14:55:39.105Z","modified":"2026-08-27T18:26:17.455822870Z","related":["SUSE-SU-2026:23066-1","SUSE-SU-2026:23068-1","SUSE-SU-2026:23221-1","SUSE-SU-2026:23231-1","SUSE-SU-2026:23237-1","openSUSE-SU-2026:21555-1"],"summary":"Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix UAF in hci_le_create_cis_sync\n\nhci_le_create_cis_sync() dereferences conn->conn_timeout after releasing\nboth rcu_read_lock() and hci_dev_lock(hdev).  The conn pointer was\nobtained from an RCU-protected iteration over hdev->conn_hash.list and\nis not valid once these locks are dropped.  A concurrent disconnect can\nfree the hci_conn between the unlock and the dereference, causing a\nuse-after-free read.\n\nThe cancellation mechanism in hci_conn_del() cannot prevent this because\nhci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL:\n\n    hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL);\n\nWhile hci_conn_del() dequeues with data=conn:\n\n    hci_cmd_sync_dequeue(hdev, NULL, conn, NULL);\n\nSince NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never\nmatches, and the pending work item is not cancelled.\n\nFix this by saving conn->conn_timeout into a local variable while the\nlocks are still held, so the stale conn pointer is never dereferenced\nafter unlock.\n\nThis is the same class of bug as the one fixed by commit 035c25007c9e\n(\"Bluetooth: hci_sync: Fix UAF on le_read_features_complete\") which\naddressed the identical pattern in a different function.\n\nThis vulnerability was identified using 0sec.ai, an open-source\nautomated security auditing platform (https://github.com/0sec-labs).","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c09b80be6ffc338634b2f5f8cfa12b6843410834"},{"fixed":"a55618c0f4cead9e59c63f5ee030d393fd70d861"},{"fixed":"a921957d39290143629eb38c4f74b9bef8035d0a"},{"fixed":"d9019210c8c30d40eb20094274cc647e352f48f7"},{"fixed":"380e67b1794a9a281a0cb592b4e62077fbd0c8ca"},{"fixed":"bfea6091e0fffb270c20e74384b660910277eb6c"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63944.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.4.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.93"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.35"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.12"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-63944.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/380e67b1794a9a281a0cb592b4e62077fbd0c8ca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63944.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63944"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63944.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}