{"id":"CVE-2026-98737","title":"Bluetooth: hci_sync: Fix inquiry cache use-after-free","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: Fix inquiry cache use-after-free\n\nThe sync command worker holds hdev->req_lock, but inquiry-cache updates\nand flushes use hdev->lock. Both hci_acl_…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 52edf1c0e59dea37b8368c4a2559dca96b2fdfea","Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 333257e6e4a7bcaaea82fd357121d0f1e6b76c7b","Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < a642f498f0b08f2aa9f4a69468db92f57a72349d","Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 8ed67535fdff40ca652bcd4ac7da68d11d01bd34","Linux 5.17"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:47:14.936Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98737","references":[{"url":"https://git.kernel.org/stable/c/52edf1c0e59dea37b8368c4a2559dca96b2fdfea"},{"url":"https://git.kernel.org/stable/c/333257e6e4a7bcaaea82fd357121d0f1e6b76c7b"},{"url":"https://git.kernel.org/stable/c/a642f498f0b08f2aa9f4a69468db92f57a72349d"},{"url":"https://git.kernel.org/stable/c/8ed67535fdff40ca652bcd4ac7da68d11d01bd34"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.503Z","slug":"CVE-2026-98737","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: Fix inquiry cache use-after-free\n\nThe sync command worker holds hdev->req_lock, but inquiry-cache updates\nand flushes use hdev->lock. Both hci_acl_create_conn_sync() and\nhci_stop_discovery_sync() look up entries and read their fields without\ntaking hdev->lock.\n\nAfter either lookup returns, a concurrent HCIINQUIRY ioctl can acquire\nhdev->lock and flush the cache, freeing the entry. The worker then reads\nthe freed entry while preparing a create-connection or remote-name-cancel\ncommand. The list traversal also races with cache updates and removal.\n\nKASAN reported these accesses:\n\n  BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5f1/0x650\n  Workqueue: hci0 hci_cmd_sync_work\n  Call Trace:\n   hci_acl_create_conn_sync+0x5f1/0x650\n   hci_cmd_sync_work+0x13c/0x290\n\n  Allocated by task 90:\n   hci_inquiry_cache_update+0x3e6/0x7d0\n   hci_inquiry_result_evt+0x3cb/0x560\n\n  Freed by task 93:\n   hci_inquiry_cache_flush+0x111/0x2b0\n   hci_inquiry+0x2f2/0x780\n   hci_sock_ioctl+0x269/0x5f0\n\n  BUG: KASAN: slab-use-after-free in hci_stop_discovery_sync+0x3b1/0x3c0\n  Workqueue: hci0 hci_cmd_sync_work\n  Call Trace:\n   hci_stop_discovery_sync+0x3b1/0x3c0\n   hci_cmd_sync_work+0x173/0x300\n\n  Allocated by task 86:\n   hci_inquiry_cache_update+0x483/0x940\n   hci_inquiry_result_evt+0x3cb/0x560\n\n  Freed by task 91:\n   hci_inquiry_cache_flush+0x13e/0x2f0\n   hci_inquiry+0x2f2/0x780\n   hci_sock_ioctl+0x269/0x5f0\n\nHold hdev->lock across each lookup and all reads from its result. Copy the\nremote address before unlocking so discovery cancellation does not retain\na cache entry pointer. Release the lock before sending synchronous HCI\ncommands, since their completion handlers may need the same lock.\n\n## Affected\n\n- `Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 52edf1c0e59dea37b8368c4a2559dca96b2fdfea`\n- `Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 333257e6e4a7bcaaea82fd357121d0f1e6b76c7b`\n- `Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < a642f498f0b08f2aa9f4a69468db92f57a72349d`\n- `Linux >= cf75ad8b41d2aa06f98f365d42a3ae8b059daddd < 8ed67535fdff40ca652bcd4ac7da68d11d01bd34`\n- `Linux 5.17`\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":[]}