{"api_version":"1","generated_at":"2026-08-23T21:33:18+00:00","cve":"CVE-2026-72336","urls":{"html":"https://cve.report/CVE-2026-72336","api":"https://cve.report/api/cve/CVE-2026-72336.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-72336","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72336"},"summary":{"title":"Bluetooth: 6lowpan: hold L2CAP conn across debugfs control","description":"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","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:06","updated_at":"2026-08-17 06:18:37"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/32c48c7f6cc8c7888e46a8c81622154ccafda5d2","name":"https://git.kernel.org/stable/c/32c48c7f6cc8c7888e46a8c81622154ccafda5d2","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff","name":"https://git.kernel.org/stable/c/d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/518aa9505fa10ea5662349e5d2efd8c9e32a820b","name":"https://git.kernel.org/stable/c/518aa9505fa10ea5662349e5d2efd8c9e32a820b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/23a83bac3356e7b211bcdcf581a31f7b536a2c24","name":"https://git.kernel.org/stable/c/23a83bac3356e7b211bcdcf581a31f7b536a2c24","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e","name":"https://git.kernel.org/stable/c/ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-72336","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72336","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6b8d4a6a03144c5996f98db7f8256267b0d72a3a ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6b8d4a6a03144c5996f98db7f8256267b0d72a3a d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6b8d4a6a03144c5996f98db7f8256267b0d72a3a 23a83bac3356e7b211bcdcf581a31f7b536a2c24 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6b8d4a6a03144c5996f98db7f8256267b0d72a3a 32c48c7f6cc8c7888e46a8c81622154ccafda5d2 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6b8d4a6a03144c5996f98db7f8256267b0d72a3a 518aa9505fa10ea5662349e5d2efd8c9e32a820b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 3.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 3.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.97 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"72336","cve":"CVE-2026-72336","epss":"0.002000000","percentile":"0.101960000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:47"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/bluetooth/6lowpan.c","net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"ba1f1ef6522e63aa5dd29805b4390ea2ccadf05e","status":"affected","version":"6b8d4a6a03144c5996f98db7f8256267b0d72a3a","versionType":"git"},{"lessThan":"d2a8dc1f619c9e0e4126bee795c39ebddd2ec8ff","status":"affected","version":"6b8d4a6a03144c5996f98db7f8256267b0d72a3a","versionType":"git"},{"lessThan":"23a83bac3356e7b211bcdcf581a31f7b536a2c24","status":"affected","version":"6b8d4a6a03144c5996f98db7f8256267b0d72a3a","versionType":"git"},{"lessThan":"32c48c7f6cc8c7888e46a8c81622154ccafda5d2","status":"affected","version":"6b8d4a6a03144c5996f98db7f8256267b0d72a3a","versionType":"git"},{"lessThan":"518aa9505fa10ea5662349e5d2efd8c9e32a820b","status":"affected","version":"6b8d4a6a03144c5996f98db7f8256267b0d72a3a","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bluetooth/6lowpan.c","net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.17"},{"lessThan":"3.17","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.97","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.97","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"3.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"3.17","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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"}],"providerMetadata":{"dateUpdated":"2026-08-17T05:12:44.492Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-72336","datePublished":"2026-08-15T05:55:44.487Z","dateReserved":"2026-08-09T03:40:39.920Z","dateUpdated":"2026-08-17T05:12:44.492Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:06","lastModifiedDate":"2026-08-17 06:18:37","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"72336","Ordinal":"1","Title":"Bluetooth: 6lowpan: hold L2CAP conn across debugfs control","CVE":"CVE-2026-72336","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"72336","Ordinal":"1","NoteData":"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","Type":"Description","Title":"Bluetooth: 6lowpan: hold L2CAP conn across debugfs control"}]}}}