{"id":"CVE-2026-53357","summary":"Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()\n\nbt_accept_dequeue() unlinks a not-yet-accepted child from the parent\naccept queue and release_sock()s it before returning, so the returned\nsk has no caller reference and is unlocked.\n\nl2cap_sock_cleanup_listen() walks these children on listening-socket\nclose.  A concurrent HCI disconnect drives hci_rx_work -\u003e\nl2cap_conn_del() which runs l2cap_chan_del() + l2cap_sock_kill() and\nfrees the child sk and its l2cap_chan; cleanup_listen() then uses both:\n\n  BUG: KASAN: slab-use-after-free in l2cap_sock_kill\n    l2cap_sock_kill / l2cap_sock_cleanup_listen / __x64_sys_close\n  Freed by: l2cap_conn_del -\u003e l2cap_sock_close_cb -\u003e l2cap_sock_kill\n\nThis is distinct from the two fixes already in this area: commit\ne83f5e24da741 (\"Bluetooth: serialize accept_q access\") serialises the\naccept_q list/poll and takes temporary refs inside bt_accept_dequeue(),\nand CVE-2025-39860 serialises the userspace close()/accept() race by\ncalling cleanup_listen() under lock_sock() in l2cap_sock_release().\nNeither covers l2cap_conn_del() running from hci_rx_work, so this UAF\nstill reproduces on current bluetooth/master.\n\nTake the reference at the source: bt_accept_dequeue() does sock_hold()\nwhile sk is still locked, before release_sock(); callers sock_put().\ncleanup_listen() pins the chan with l2cap_chan_hold_unless_zero() under\na brief child sk lock (serialising vs l2cap_sock_teardown_cb()), drops\nit before l2cap_chan_lock(), and skips a duplicate l2cap_sock_kill() on\nSOCK_DEAD.  conn-\u003elock is not taken here: cleanup_listen() runs under\nthe parent sk lock and that would invert\nconn-\u003elock -\u003e chan-\u003elock -\u003e sk_lock (lockdep).\n\nKASAN/SMP: an unprivileged listen/close vs HCI-disconnect race produced\n12 use-after-free reports per run before this change; 0, and no lockdep\nreport, over 1600+ raced iterations after it on bluetooth/master.","modified":"2026-07-16T03:32:16.183631695Z","published":"2026-07-02T13:43:17.077Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53357.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57"},{"type":"WEB","url":"https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919"},{"type":"WEB","url":"https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022"},{"type":"WEB","url":"https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53357.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53357"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"15f02b91056253e8cdc592888f431da0731337b8"},{"fixed":"751de6ec671fe75ad9cf65a0638d2a06b6a5984d"},{"fixed":"407217734835d21d4e0105ebf347860dc1806f88"},{"fixed":"7eebd4c2c86f573af87ff165d08a83432eb0b919"},{"fixed":"5d86d2f1b4d9a508c441d3e45277ae1a73cfed57"},{"fixed":"87c543e2f78d0871f271df92dab98901bbd5b6f5"},{"fixed":"added1213395071470a900cc845a042fb51882a6"},{"fixed":"a5ca86a6097a8b030ca3226cd300b17ed330f966"},{"fixed":"ab1513597c6cf17cd1ad2a21e3b045421b48e022"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-53357.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.7.0"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.142"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.92"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-53357.json"}}],"schema_version":"1.7.5"}