{"id":"CVE-2026-53357","state":"PUBLISHED","title":"Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()","description":"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 ->\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 -> l2cap_sock_close_cb -> 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->lock is not taken here: cleanup_listen() runs under\nthe parent sk lock and that would invert\nconn->lock -> chan->lock -> 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.","publishedAt":"2026-07-02T13:43:17.077Z","updatedAt":"2026-10-19T20:07:44.061Z","severity":{"score":8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"751de6ec671fe75ad9cf65a0638d2a06b6a5984d","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"407217734835d21d4e0105ebf347860dc1806f88","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"7eebd4c2c86f573af87ff165d08a83432eb0b919","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"5d86d2f1b4d9a508c441d3e45277ae1a73cfed57","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"87c543e2f78d0871f271df92dab98901bbd5b6f5","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"added1213395071470a900cc845a042fb51882a6","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"a5ca86a6097a8b030ca3226cd300b17ed330f966","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"ab1513597c6cf17cd1ad2a21e3b045421b48e022","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/af_bluetooth.c","net/bluetooth/iso.c","net/bluetooth/l2cap_sock.c","net/bluetooth/rfcomm/sock.c","net/bluetooth/sco.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/af_bluetooth.c","net/bluetooth/iso.c","net/bluetooth/l2cap_sock.c","net/bluetooth/rfcomm/sock.c","net/bluetooth/sco.c"]}],"references":["https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d","https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88","https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919","https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57","https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5","https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6","https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966","https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53357.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53357","state":"PUBLISHED","datePublished":"2026-07-02T13:43:17.077Z","dateUpdated":"2026-10-19T20:07:44.061Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.400Z"},"containers":{"cna":{"title":"Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()","descriptions":[{"lang":"en","value":"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 ->\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 -> l2cap_sock_close_cb -> 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->lock is not taken here: cleanup_listen() runs under\nthe parent sk lock and that would invert\nconn->lock -> chan->lock -> 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"751de6ec671fe75ad9cf65a0638d2a06b6a5984d","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"407217734835d21d4e0105ebf347860dc1806f88","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"7eebd4c2c86f573af87ff165d08a83432eb0b919","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"5d86d2f1b4d9a508c441d3e45277ae1a73cfed57","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"87c543e2f78d0871f271df92dab98901bbd5b6f5","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"added1213395071470a900cc845a042fb51882a6","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"a5ca86a6097a8b030ca3226cd300b17ed330f966","versionType":"git"},{"version":"15f02b91056253e8cdc592888f431da0731337b8","status":"affected","lessThan":"ab1513597c6cf17cd1ad2a21e3b045421b48e022","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/af_bluetooth.c","net/bluetooth/iso.c","net/bluetooth/l2cap_sock.c","net/bluetooth/rfcomm/sock.c","net/bluetooth/sco.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.7","versionType":"semver"},{"version":"5.10.259","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/af_bluetooth.c","net/bluetooth/iso.c","net/bluetooth/l2cap_sock.c","net/bluetooth/rfcomm/sock.c","net/bluetooth/sco.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d"},{"url":"https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88"},{"url":"https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919"},{"url":"https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57"},{"url":"https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5"},{"url":"https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6"},{"url":"https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966"},{"url":"https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - The race is driven through Bluetooth L2CAP/HCI connection and disconnect handling from a nearby peer, so it is limited to Bluetooth-adjacent reachability rather than routable network access. The local listener/close side is accounted for in PR.\nAC:L - This is a race, but the attacker can reasonably control the listener close timing and the Bluetooth peer disconnect timing. The commit reports reliable unprivileged raced iterations, so no uncontrollable condition is required.\nPR:L - Creating, binding to a dynamic PSM, listening on, and closing non-raw L2CAP sockets does not require capabilities; only raw sockets or reserved PSMs need privileges. A basic unprivileged local user on the target can set up the vulnerable listener.\nUI:N - No victim user action is required once the attacker can run the unprivileged local setup and control the Bluetooth peer. The trigger is socket close racing HCI disconnect processing.\nS:U - The corruption is within the Linux kernel Bluetooth/socket subsystem and impacts the same kernel security authority. It is not a VM escape or cross-scope boundary bypass.\nC:H - The bug is a use-after-free of both the child sock and its l2cap_chan, and freed kernel heap objects can be reclaimed and used for disclosure primitives. Per kernel CVSS guidance, UAF memory corruption supports high confidentiality impact.\nI:H - The stale sock/channel pointers are used after l2cap_conn_del frees them, including through cleanup and kill paths, making heap grooming and control-flow or write-primitive exploitation plausible. Per guidance, UAF memory corruption supports high integrity impact.\nA:H - The observed failure is a KASAN slab-use-after-free in kernel Bluetooth cleanup, which can crash or oops the kernel. Repeated triggering can deny availability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:35:06.665Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.10.259"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.6.142"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.7","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-53357","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:28:47.902686Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:07:44.061Z"}}]}}}