{"id":"CVE-2026-98735","title":"Bluetooth: hci_core: Serialize ACL scheduling with channel deletion","summary":"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->conn and…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 51f95ea451f25d7e3f048c0f438f04fa74688aae","Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd","Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 4fda8f0abeea9929036446d89a476fb8298abcb0","Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < f4845ab191a4f686a5da481fbba90ed73bb693b0","Linux 3.3"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:47:13.062Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98735","references":[{"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"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.504Z","slug":"CVE-2026-98735","body":"## Overview\n\nIn 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->conn 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.\n\n## Affected\n\n- `Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 51f95ea451f25d7e3f048c0f438f04fa74688aae`\n- `Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 86e9708f9d19a7f1bd5dc9c1652d07707f79f5bd`\n- `Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < 4fda8f0abeea9929036446d89a476fb8298abcb0`\n- `Linux >= 3eff45eaf81780dad25c167bbaafa7d25ae407da < f4845ab191a4f686a5da481fbba90ed73bb693b0`\n- `Linux 3.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}