{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72336", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.920Z", "datePublished": "2026-08-15T05:55:44.487Z", "dateUpdated": "2026-08-17T05:12:44.492Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:12:44.492Z" }, "descriptions": [ { "lang": "en", "value": "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->l2cap_data and before\nlowpan_control_write() later dereferences conn->hcon. 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->l2cap_data. the L2CAP disconnect callback.\n 2. get_l2cap_conn() drops hdev 2. l2cap_conn_del() clears\n protection and returns conn. hcon->l2cap_data and drops the\n L2CAP connection reference.\n 3. lowpan_control_write() reads 3. hci_conn_del() removes and drops\n conn->hcon. 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" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/6lowpan.c", "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a", "lessThan": "ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e", "status": "affected", "versionType": "git" }, { "version": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a", "lessThan": "d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff", "status": "affected", "versionType": "git" }, { "version": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a", "lessThan": "23a83bac3356e7b211bcdcf581a31f7b536a2c24", "status": "affected", "versionType": "git" }, { "version": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a", "lessThan": "32c48c7f6cc8c7888e46a8c81622154ccafda5d2", "status": "affected", "versionType": "git" }, { "version": "6b8d4a6a03144c5996f98db7f8256267b0d72a3a", "lessThan": "518aa9505fa10ea5662349e5d2efd8c9e32a820b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/6lowpan.c", "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "3.17", "status": "affected" }, { "version": "0", "lessThan": "3.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.17", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e" }, { "url": "https://git.kernel.org/stable/c/d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff" }, { "url": "https://git.kernel.org/stable/c/23a83bac3356e7b211bcdcf581a31f7b536a2c24" }, { "url": "https://git.kernel.org/stable/c/32c48c7f6cc8c7888e46a8c81622154ccafda5d2" }, { "url": "https://git.kernel.org/stable/c/518aa9505fa10ea5662349e5d2efd8c9e32a820b" } ], "title": "Bluetooth: 6lowpan: hold L2CAP conn across debugfs control", "x_generator": { "engine": "bippy-1.2.0" } } } }