{"id":"CVE-2022-49909","summary":"Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix use-after-free in l2cap_conn_del()\n\nWhen l2cap_recv_frame() is invoked to receive data, and the cid is\nL2CAP_CID_A2MP, if the channel does not exist, it will create a channel.\nHowever, after a channel is created, the hold operation of the channel\nis not performed. In this case, the value of channel reference counting\nis 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del()\ninvokes the close hook function of A2MP to release the channel. Then\n l2cap_chan_unlock(chan) will trigger UAF issue.\n\nThe process is as follows:\nReceive data:\nl2cap_data_channel()\n    a2mp_channel_create()  ---\u003echannel ref is 2\n    l2cap_chan_put()       ---\u003echannel ref is 1\n\nTriger event:\n    hci_error_reset()\n        hci_dev_do_close()\n        ...\n        l2cap_disconn_cfm()\n            l2cap_conn_del()\n                l2cap_chan_hold()    ---\u003echannel ref is 2\n                l2cap_chan_del()     ---\u003echannel ref is 1\n                a2mp_chan_close_cb() ---\u003echannel ref is 0, release channel\n                l2cap_chan_unlock()  ---\u003eUAF of channel\n\nThe detailed Call Trace is as follows:\nBUG: KASAN: use-after-free in __mutex_unlock_slowpath+0xa6/0x5e0\nRead of size 8 at addr ffff8880160664b8 by task kworker/u11:1/7593\nWorkqueue: hci0 hci_error_reset\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0xcd/0x134\n print_report.cold+0x2ba/0x719\n kasan_report+0xb1/0x1e0\n kasan_check_range+0x140/0x190\n __mutex_unlock_slowpath+0xa6/0x5e0\n l2cap_conn_del+0x404/0x7b0\n l2cap_disconn_cfm+0x8c/0xc0\n hci_conn_hash_flush+0x11f/0x260\n hci_dev_close_sync+0x5f5/0x11f0\n hci_dev_do_close+0x2d/0x70\n hci_error_reset+0x9e/0x140\n process_one_work+0x98a/0x1620\n worker_thread+0x665/0x1080\n kthread+0x2e4/0x3a0\n ret_from_fork+0x1f/0x30\n \u003c/TASK\u003e\n\nAllocated by task 7593:\n kasan_save_stack+0x1e/0x40\n __kasan_kmalloc+0xa9/0xd0\n l2cap_chan_create+0x40/0x930\n amp_mgr_create+0x96/0x990\n a2mp_channel_create+0x7d/0x150\n l2cap_recv_frame+0x51b8/0x9a70\n l2cap_recv_acldata+0xaa3/0xc00\n hci_rx_work+0x702/0x1220\n process_one_work+0x98a/0x1620\n worker_thread+0x665/0x1080\n kthread+0x2e4/0x3a0\n ret_from_fork+0x1f/0x30\n\nFreed by task 7593:\n kasan_save_stack+0x1e/0x40\n kasan_set_track+0x21/0x30\n kasan_set_free_info+0x20/0x30\n ____kasan_slab_free+0x167/0x1c0\n slab_free_freelist_hook+0x89/0x1c0\n kfree+0xe2/0x580\n l2cap_chan_put+0x22a/0x2d0\n l2cap_conn_del+0x3fc/0x7b0\n l2cap_disconn_cfm+0x8c/0xc0\n hci_conn_hash_flush+0x11f/0x260\n hci_dev_close_sync+0x5f5/0x11f0\n hci_dev_do_close+0x2d/0x70\n hci_error_reset+0x9e/0x140\n process_one_work+0x98a/0x1620\n worker_thread+0x665/0x1080\n kthread+0x2e4/0x3a0\n ret_from_fork+0x1f/0x30\n\nLast potentially related work creation:\n kasan_save_stack+0x1e/0x40\n __kasan_record_aux_stack+0xbe/0xd0\n call_rcu+0x99/0x740\n netlink_release+0xe6a/0x1cf0\n __sock_release+0xcd/0x280\n sock_close+0x18/0x20\n __fput+0x27c/0xa90\n task_work_run+0xdd/0x1a0\n exit_to_user_mode_prepare+0x23c/0x250\n syscall_exit_to_user_mode+0x19/0x50\n do_syscall_64+0x42/0x80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nSecond to last potentially related work creation:\n kasan_save_stack+0x1e/0x40\n __kasan_record_aux_stack+0xbe/0xd0\n call_rcu+0x99/0x740\n netlink_release+0xe6a/0x1cf0\n __sock_release+0xcd/0x280\n sock_close+0x18/0x20\n __fput+0x27c/0xa90\n task_work_run+0xdd/0x1a0\n exit_to_user_mode_prepare+0x23c/0x250\n syscall_exit_to_user_mode+0x19/0x50\n do_syscall_64+0x42/0x80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd","modified":"2026-04-10T04:53:32.940019Z","published":"2025-05-01T14:10:52.331Z","related":["SUSE-SU-2025:01918-1","SUSE-SU-2025:01966-1","SUSE-SU-2025:01983-1","SUSE-SU-2025:02173-1","SUSE-SU-2025:02262-1"],"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0d0e2d032811280b927650ff3c15fe5020e82533"},{"type":"WEB","url":"https://git.kernel.org/stable/c/17c6164854f8bb80bf76f32b2c2f199c16b53703"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7f7bfdd9a9af3b12c33d9da9a012e7f4d5c91f4b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8f7e4cf0694149a5d999d676ebd9ecf1b4cb2cc9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3a7b2ac64de232edb67279e804932cb42f0b52a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c1f594dddd9ffd747c39f49cc5b67a9b7677d2ab"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d9ec6e2fbd4a565b2345d4852f586b7ae3ab41fd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/db4a0783ed78beb2ebaa32f5f785bfd79c580689"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d255c861e268ba342e855244639a15f12d7a0bf2"},{"fixed":"db4a0783ed78beb2ebaa32f5f785bfd79c580689"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5bb395334392891dffae5a0e8f37dbe1d70496c9"},{"fixed":"17c6164854f8bb80bf76f32b2c2f199c16b53703"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"bbd1fdb0e1adf827997a93bf108f20ede038e56e"},{"fixed":"7f7bfdd9a9af3b12c33d9da9a012e7f4d5c91f4b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"098e07ef0059296e710a801cdbd74b59016e6624"},{"fixed":"c1f594dddd9ffd747c39f49cc5b67a9b7677d2ab"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"de5d4654ac6c22b1be756fdf7db18471e7df01ea"},{"fixed":"d9ec6e2fbd4a565b2345d4852f586b7ae3ab41fd"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"f32d5615a78a1256c4f557ccc6543866e75d03f4"},{"fixed":"a3a7b2ac64de232edb67279e804932cb42f0b52a"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d0be8347c623e0ac4202a1d4e0373882821f56b0"},{"fixed":"8f7e4cf0694149a5d999d676ebd9ecf1b4cb2cc9"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d0be8347c623e0ac4202a1d4e0373882821f56b0"},{"fixed":"0d0e2d032811280b927650ff3c15fe5020e82533"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"59a55ec33a54a7179fa178f8aaf8b1cb8e63bd93"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49909.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.9.333"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.10.0"},{"fixed":"4.14.299"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"4.19.265"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.224"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.154"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.0.8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49909.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}