{ "affected": [ { "ranges": [ { "events": [ { "introduced": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a" }, { "fixed": "ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e" }, { "fixed": "d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff" }, { "fixed": "23a83bac3356e7b211bcdcf581a31f7b536a2c24" }, { "fixed": "32c48c7f6cc8c7888e46a8c81622154ccafda5d2" }, { "fixed": "518aa9505fa10ea5662349e5d2efd8c9e32a820b" } ], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "type": "GIT" } ] }, { "package": { "ecosystem": "Linux", "name": "Kernel" }, "ranges": [ { "events": [ { "introduced": "3.17.0" }, { "fixed": "6.6.145" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.7.0" }, { "fixed": "6.12.97" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.13.0" }, { "fixed": "6.18.40" } ], "type": "ECOSYSTEM" }, { "events": [ { "introduced": "6.19.0" }, { "fixed": "7.1.5" } ], "type": "ECOSYSTEM" } ] } ], "database_specific": { "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72336.json" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: 6lowpan: hold L2CAP conn across debugfs control\n\nget_l2cap_conn() looks up an LE hci_conn under hdev protection, but\nthen drops that protection before reading hcon-\u003el2cap_data and before\nlowpan_control_write() later dereferences conn-\u003ehcon. A disconnect or\ndevice close can tear down the same L2CAP connection in that window.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\n6LoWPAN control write: HCI disconnect/device close:\n 1. get_l2cap_conn() finds hcon 1. hci_disconn_cfm() dispatches\n and hcon-\u003el2cap_data. the L2CAP disconnect callback.\n 2. get_l2cap_conn() drops hdev 2. l2cap_conn_del() clears\n protection and returns conn. hcon-\u003el2cap_data and drops the\n L2CAP connection reference.\n 3. lowpan_control_write() reads 3. hci_conn_del() removes and drops\n conn-\u003ehcon. the HCI connection.\n\nTake a reference to the L2CAP connection with\nl2cap_conn_hold_unless_zero() while hdev is still locked, and drop that\nreference after the debugfs command's last use of conn. This mirrors the\nexisting L2CAP ACL receive-side handoff and keeps the connection\ndereferenceable after leaving hdev protection. Export the existing helper\nso the bluetooth_6lowpan module can use the same lifetime primitive.\n\nValidation reproduced this kernel report:\nBUG: KASAN: slab-use-after-free in lowpan_control_write+0x374/0x520\nThe buggy address belongs to the object at ffff888111b9d000 which belongs\nto the cache kmalloc-1k of size 1024\nThe buggy address is located 0 bytes inside of freed 1024-byte region\n[ffff888111b9d000, ffff888111b9d400)\nRead of size 8\nCall trace:\n dump_stack_lvl+0x66/0xa0\n print_report+0xce/0x5f0\n lowpan_control_write+0x374/0x520 (net/bluetooth/6lowpan.c:1131)\n srso_alias_return_thunk+0x5/0xfbef5\n __virt_addr_valid+0x19f/0x330\n kasan_report+0xe0/0x110\n __debugfs_file_get+0xf7/0x400\n full_proxy_write+0x9e/0xd0\n vfs_write+0x1b0/0x810\n ksys_write+0xd2/0x170\n dnotify_flush+0x32/0x220\n do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nAllocated by task stack:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x17/0x60\n __kasan_kmalloc+0xaa/0xb0\n l2cap_conn_add+0x45/0x520\n l2cap_chan_connect+0xac6/0xd90\n l2cap_sock_connect+0x216/0x350\n __sys_connect+0x101/0x130\n __x64_sys_connect+0x40/0x50\n do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nFreed by task stack:\n kasan_save_stack+0x33/0x60\n kasan_save_track+0x17/0x60\n kasan_save_free_info+0x3b/0x60\n __kasan_slab_free+0x5f/0x80\n kfree+0x313/0x590\n hci_conn_hash_flush+0xc0/0x140\n hci_dev_close_sync+0x41a/0xb00\n hci_dev_close+0x12f/0x160\n hci_sock_ioctl+0x157/0x570\n sock_do_ioctl+0xf7/0x210\n sock_ioctl+0x32f/0x490\n __x64_sys_ioctl+0xc7/0x110\n do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n kasan_record_aux_stack+0xa7/0xc0\n insert_work+0x32/0x100\n __queue_work+0x262/0xa60\n queue_work_on+0xad/0xb0\n l2cap_connect_cfm+0x4ef/0x670\n hci_le_remote_feat_complete_evt+0x247/0x430\n hci_event_packet+0x360/0x6f0\n hci_rx_work+0x2ae/0x7a0\n process_one_work+0x4fd/0xbc0\n worker_thread+0x2d8/0x570\n kthread+0x1ad/0x1f0\n ret_from_fork+0x3c9/0x540\n ret_from_fork_asm+0x1a/0x30", "id": "CVE-2026-72336", "modified": "2026-08-18T03:31:10.574077983Z", "published": "2026-08-15T05:55:44.487Z", "references": [ { "type": "WEB", "url": "https://git.kernel.org/stable/c/23a83bac3356e7b211bcdcf581a31f7b536a2c24" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/32c48c7f6cc8c7888e46a8c81622154ccafda5d2" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/518aa9505fa10ea5662349e5d2efd8c9e32a820b" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff" }, { "type": "ADVISORY", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72336.json" }, { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72336" }, { "type": "PACKAGE", "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git" } ], "schema_version": "1.9.0", "summary": "Bluetooth: 6lowpan: hold L2CAP conn across debugfs control" }