Search Results (152 CVEs found)

CVE Vendors Products Updated CVSS v3.1
CVE-2026-74530 1 Linux 1 Linux Kernel 2026-08-17 8.8 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback There is theoretical UAF if the conn is freed while the hci_sync task is running. Hold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to match the previous behavior.
CVE-2026-74506 1 Linux 1 Linux Kernel 2026-08-17 7.8 High
In the Linux kernel, the following vulnerability has been resolved: afs: Fix UAF when sending a message In afs_make_call(), there's a race with async call reception and destruction. If a call is dispatched that doesn't have call->write_iter set (used to specify the data content for FS.StoreData), then the first rxrpc_kernel_send_data() will not set MSG_MORE in the msghdr. Once rxrpc_send_data() queues the last request packet, the response could come in at any time and cause the call to be completed and put. However, afs_make_call() will look at the call again to see it ->write_iter should be handled - something it's only allowed to do if it has its own ref on the call. Whilst this is the case for synchronous calls, it isn't true for async calls such as FS.FetchData. There's also a potential UAF in afs_make_call() in the event that an asynchronous call is being sent, but the call fails in some way (e.g. it gets aborted from the server). The problem there is that afs_make_call() tries to abort a call if the rxrpc send fails, but the asynchronous notification from rxrpc may have caused the afs_call to be torn down. generic/650 plays games with randomly taking CPUs offline, and can interject a significant delay such that the call is deallocated before afs_make_call() gets to check call->write_iter - and a UAF ensues (caught by KASAN). BUG: KASAN: slab-use-after-free in afs_make_call+0x1c90/0x2210 [kafs] Read of size 8 at addr ffff888035e050e8 by task fsstress/1409 Fix this by making afs_make_op_call() give the op->call its own ref rather than transferring the caller's ref to it and then dropping the ref when afs_make_call() returns. This also means that the afs_make_call() func never loses its ref on the call now.
CVE-2026-43632 2 Ggml, Ggml-org 2 Llama.cpp, Llama.cpp 2026-08-14 8.1 High
llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in llama-server affecting six tokenization endpoints (/tokenize, /detokenize, /infill, /apply-template, /rerank, and /anthropic/count_tokens) that bypass the task queue and access ctx_server.vocab directly on HTTP worker threads. Attackers can exploit a time-of-check-time-of-use race condition where the main thread destroys and frees vocab after the synchronization lock is released but before the handler finishes using it, causing a crash or potential code execution when --sleep-idle-seconds is configured.
CVE-2026-68200 1 Linux 1 Linux Kernel 2026-08-14 7.8 High
In the Linux kernel, the following vulnerability has been resolved: ALSA: timer: don't re-enter an instance callback that is still running The userspace-driven timer (utimer) TRIGGER ioctl calls snd_timer_interrupt() directly with no serialization, so two threads triggering the same utimer can run snd_timer_interrupt() on one snd_timer concurrently. snd_timer_process_callbacks() drops timer->lock around each instance callback and marks the in-flight callback with the single SNDRV_TIMER_IFLG_CALLBACK bit; snd_timer_close_locked() waits on that bit to drain an in-flight callback before freeing the instance. The bit cannot represent two concurrent callbacks: when a second interrupt re-queues an instance whose callback is still running, both run at once, the first to finish clears the bit, and the close-path drain then frees the instance (and its callback_data) while the other callback is still live - a use-after-free reachable by any user able to open /dev/snd/timer, both via a user timer instance and via a sequencer queue timer bound to the utimer. snd_timer_interrupt() sets IFLG_CALLBACK before dropping timer->lock, so a concurrent interrupt already observes it under the lock. Skip re-queuing an instance (and its slaves) to the ack/sack list while its callback is in flight; the accumulated pticks are delivered on the next tick, so no event is lost.
CVE-2026-68381 1 Linux 1 Linux Kernel 2026-08-13 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: ksmbd: pin conn during async oplock break notification smb2_oplock_break_noti() and smb2_lease_break_noti() store a ksmbd_conn pointer in an async ksmbd_work and then queue that work on ksmbd-io. The work only increments conn->r_count, which prevents teardown from passing the pending-request wait after the increment, but it does not pin the struct ksmbd_conn object. If connection teardown races with an oplock break notification, the last conn reference can be dropped before the queued worker finishes. The worker then uses the freed conn in ksmbd_conn_write() and ksmbd_conn_r_count_dec(). Take a real conn reference when publishing the conn pointer to the async work item, and drop it after the notification work has decremented r_count. Apply the same lifetime rule to lease break notification, which uses the same work->conn pattern.
CVE-2026-68152 1 Linux 1 Linux Kernel 2026-08-13 7.8 High
In the Linux kernel, the following vulnerability has been resolved: amt: fix use-after-free in AMT delayed works When an AMT device is removed, pending delayed works can still access the freed amt_dev structure, which may result in kernel crashes or memory corruption. amt_dev_stop() cancels req_wq and discovery_wq with cancel_delayed_work_sync(), but these works can be scheduled again from event_wq after the cancellation. This allows delayed works to access the freed amt_dev structure after the netdev has been released. The following is a simple race scenario: CPU0 CPU1 amt_dev_stop() cancel_delayed_work_sync() amt_event_work() mod_delayed_work(req_wq) free netdev req_wq accesses freed amt_dev Use disable_delayed_work_sync() in amt_dev_stop() to prevent req_wq and discovery_wq from being queued again and wait for running work items to complete. The delayed works are disabled after initialization in amt_newlink() and enabled only when the device is successfully opened. This keeps the delayed work lifecycle synchronized with the lifetime of the AMT device.
CVE-2026-68286 1 Linux 1 Linux Kernel 2026-08-13 5.3 Medium
In the Linux kernel, the following vulnerability has been resolved: drop_monitor: perform u64_stats updates under IRQ-disabled section In net_dm_packet_trace_kfree_skb_hit() and net_dm_hw_trap_packet_probe(), u64_stats_update_begin() / u64_stats_inc() / u64_stats_update_end() were called after spin_unlock_irqrestore(&...drop_queue.lock, flags), when local IRQs had already been re-enabled. Tracepoint probes can execute in IRQ or softirq context. On 32-bit architectures, u64_stats_update_begin() disables preemption but not interrupts, relying on seqcount writes. If a nested interrupt occurs on the same CPU during the 64-bit stats update, the reentrant seqcount update can corrupt the seqcount state or stats value. Fix this by performing the 64-bit per-CPU stats update before releasing drop_queue.lock via spin_unlock_irqrestore(), ensuring local interrupts remain disabled during the u64_stats update.
CVE-2026-53286 1 Linux 1 Linux Kernel 2026-08-12 7.8 High
In the Linux kernel, the following vulnerability has been resolved: idpf: fix double free and use-after-free in aux device error paths When auxiliary_device_add() fails in idpf_plug_vport_aux_dev() or idpf_plug_core_aux_dev(), the err_aux_dev_add label calls auxiliary_device_uninit() and falls through to err_aux_dev_init. The uninit call will trigger put_device(), which invokes the release callback (idpf_vport_adev_release / idpf_core_adev_release) that frees iadev. The fall-through then reads adev->id from the freed iadev for ida_free() and double-frees iadev with kfree(). Free the IDA slot and clear the back-pointer before uninit, while adev is still valid, then return immediately. Commit 65637c3a1811 ("idpf: fix UAF in RDMA core aux dev deinitialization") fixed the same use-after-free in the matching unplug path in this file but missed both probe error paths.
CVE-2026-64093 1 Linux 1 Linux Kernel 2026-08-11 8.8 High
In the Linux kernel, the following vulnerability has been resolved: batman-adv: tp_meter: directly shut down timer on cleanup batadv_tp_sender_cleanup() was calling timer_delete_sync() followed by timer_delete() to guard against the timer handler re-arming itself between the two calls. This double-deletion hack relied on the sending status being set to 0 to suppress re-arming. Replace both calls with a single timer_shutdown_sync(). This function both waits for any running timer callback to complete (like timer_delete_sync()) and permanently disarms the timer so it cannot be re-armed afterwards, making re-arming prevention unconditional and self-documenting. The re-arming property is also required because otherwise: 1. context 0 (batadv_tp_recv_ack()) checks in batadv_tp_reset_sender_timer() if sending is still 1 -> it is 2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in this process forces the kthread to stop timer in batadv_tp_sender_cleanup() 3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the timer -> but the reference for it is already gone
CVE-2026-31404 1 Linux 1 Linux Kernel 2026-08-11 5.5 Medium
This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.
CVE-2024-39508 2 Linux, Redhat 2 Linux Kernel, Enterprise Linux 2026-08-04 7.8 High
In the Linux kernel, the following vulnerability has been resolved: io_uring/io-wq: Use set_bit() and test_bit() at worker->flags Utilize set_bit() and test_bit() on worker->flags within io_uring/io-wq to address potential data races. The structure io_worker->flags may be accessed through various data paths, leading to concurrency issues. When KCSAN is enabled, it reveals data races occurring in io_worker_handle_work and io_wq_activate_free_worker functions. BUG: KCSAN: data-race in io_worker_handle_work / io_wq_activate_free_worker write to 0xffff8885c4246404 of 4 bytes by task 49071 on cpu 28: io_worker_handle_work (io_uring/io-wq.c:434 io_uring/io-wq.c:569) io_wq_worker (io_uring/io-wq.c:?) <snip> read to 0xffff8885c4246404 of 4 bytes by task 49024 on cpu 5: io_wq_activate_free_worker (io_uring/io-wq.c:? io_uring/io-wq.c:285) io_wq_enqueue (io_uring/io-wq.c:947) io_queue_iowq (io_uring/io_uring.c:524) io_req_task_submit (io_uring/io_uring.c:1511) io_handle_tw_list (io_uring/io_uring.c:1198) <snip> Line numbers against commit 18daea77cca6 ("Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm"). These races involve writes and reads to the same memory location by different tasks running on different CPUs. To mitigate this, refactor the code to use atomic operations such as set_bit(), test_bit(), and clear_bit() instead of basic "and" and "or" operations. This ensures thread-safe manipulation of worker flags. Also, move `create_index` to avoid holes in the structure.
CVE-2024-39292 1 Linux 1 Linux Kernel 2026-08-04 7.8 High
In the Linux kernel, the following vulnerability has been resolved: um: Add winch to winch_handlers before registering winch IRQ Registering a winch IRQ is racy, an interrupt may occur before the winch is added to the winch_handlers list. If that happens, register_winch_irq() adds to that list a winch that is scheduled to be (or has already been) freed, causing a panic later in winch_cleanup(). Avoid the race by adding the winch to the winch_handlers list before registering the IRQ, and rolling back if um_request_irq() fails.
CVE-2026-64025 1 Linux 1 Linux Kernel 2026-07-30 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: bpf, skmsg: fix verdict sk_data_ready racing with ktls rx sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and defers to psock->saved_data_ready when a TLS RX context is present, avoiding a conflict with the TLS strparser's ownership of the receive queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types with ktls"). sk_psock_verdict_data_ready() has no equivalent guard. When a socket is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready as rx_ctx->saved_data_ready. On data arrival: tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready -> saved_data_ready() = sk_psock_verdict_data_ready() -> tcp_read_skb() drains sk_receive_queue via __skb_unlink() without calling tcp_eat_skb(), so copied_seq is not advanced. tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned (potentially freed) skb. tls_decrypt_sg() subsequently walks that frag_list: use-after-free. Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context is present, call psock->saved_data_ready (sock_def_readable) to wake recv() waiters and return immediately, leaving the receive queue untouched. TLS retains sole ownership of the queue and decrypts the record normally through tls_sw_recvmsg().
CVE-2026-64541 1 Linux 1 Linux Kernel 2026-07-30 9.8 Critical
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket smc_cdc_rx_handler() looks up the connection by token under the link group's conns_lock, drops the lock, and then dereferences conn and the smc_sock derived from it, ending in sock_hold(&smc->sk) inside smc_cdc_msg_recv(). No reference is held across the lock release. The only reference pinning the socket while the connection is discoverable in the link group is taken in smc_lgr_register_conn() (sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both under conns_lock. Once the handler drops conns_lock, a concurrent close() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn() can drop that reference and free the smc_sock, so the handler's later sock_hold() runs on freed memory: WARNING: lib/refcount.c:25 at refcount_warn_saturate Workqueue: rxe_wq do_work refcount_warn_saturate (lib/refcount.c:25) smc_cdc_msg_recv (net/smc/smc_cdc.c:430) smc_cdc_rx_handler (net/smc/smc_cdc.c:502) smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445) tasklet_action_common (kernel/softirq.c:938) handle_softirqs (kernel/softirq.c:622) Kernel panic - not syncing: panic_on_warn set Only SMC-R is affected. The SMC-D receive tasklet is stopped by tasklet_kill(&conn->rx_tsklet) in smc_conn_free() before the connection is unregistered, so it cannot run concurrently with the free. Take the socket reference while still holding conns_lock, so the registration reference can no longer be the last one, and drop it once the handler is done.
CVE-2025-71274 1 Linux 1 Linux Kernel 2026-07-30 7.8 High
In the Linux kernel, the following vulnerability has been resolved: rpmsg: core: fix race in driver_override_show() and use core helper The driver_override_show function reads the driver_override string without holding the device_lock. However, the store function modifies and frees the string while holding the device_lock. This creates a race condition where the string can be freed by the store function while being read by the show function, leading to a use-after-free. To fix this, replace the rpmsg_string_attr macro with explicit show and store functions. The new driver_override_store uses the standard driver_set_override helper. Since the introduction of driver_set_override, the comments in include/linux/rpmsg.h have stated that this helper must be used to set or clear driver_override, but the implementation was not updated until now. Because driver_set_override modifies and frees the string while holding the device_lock, the new driver_override_show now correctly holds the device_lock during the read operation to prevent the race. Additionally, since rpmsg_string_attr has only ever been used for driver_override, removing the macro simplifies the code.
CVE-2026-53264 1 Linux 1 Linux Kernel 2026-07-29 7.8 High
In the Linux kernel, the following vulnerability has been resolved: net/sched: act_api: use RCU with deferred freeing for action lifecycle When NEWTFILTER and DELFILTER are run concurrently it is possible to create a race with an associated action. Let's illustrate with CPU0 running NEWTFILTER and CPU1 running DELFILTER: 0: mutex_lock() <-- holds the idr lock 0: rcu_read_lock() 0: p = idr_find(idr, index) <-- action p is valid (RCU protects IDR) 0: mutex_unlock() <-- releases the idr lock 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) <-- Action removed from IDR 1: mutex_unlock() <-- mutex released allowing us to delete the action 1: tcf_action_cleanup(p); kfree(p) <-- Kfrees p immediately, no deferral 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- ouch, UAF p points to freed memory This patch fixes the race condition between NEWTFILTER and DELFILTER by adding struct rcu_head to tc_action used in the deferral and introducing a call_rcu() in the delete path to defer the final kfree(). Note: this is a revert of commit d7fb60b9cafb ("net_sched: get rid of tcfa_rcu") but also modernization/simplification to directly use kfree_rcu(). Let's illustrate the new restored code path: 0: rcu_read_lock() 1: refcount_dec_and_mutex_lock() <-- refcnt 1->0, mutex held 1: idr_remove(idr, index) 1: mutex_unlock() 1: call_rcu(&p->tcfa_rcu, tcf_action_rcu_free) <-- defer kfree after grace period 0: p = idr_find(idr, index) 0: refcount_inc_not_zero(&p->tcfa_refcnt) <-- fails, refcnt already 0 1: rcu_read_unlock() <-- release so freeing can run after grace period After CPU1 calls idr_remove(), the object is no longer reachable through the IDR. CPU0's subsequent idr_find() will return NULL, and even if it still held a stale pointer, the immediate kfree() is now deferred until after the RCU grace period, so no UAF can occur.
CVE-2026-64010 1 Linux 1 Linux Kernel 2026-07-26 8.8 High
In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: Fix use-after-free race in nfc_llcp_recv_cc() A race condition exists in the NFC LLCP connection state machine where the connection acceptance packet (CC) can be processed concurrently with socket release. This can lead to a use-after-free of the socket object. When nfc_llcp_recv_cc() moves the socket from the connecting_sockets list to the sockets list, it does so without holding the socket lock. If llcp_sock_release() is executing concurrently, it might have already unlinked the socket and dropped its references, which can result in nfc_llcp_recv_cc() linking a freed socket into the live list. Fix this by holding lock_sock() during the state transition and list movement in nfc_llcp_recv_cc(). After acquiring the lock, check if the socket is still hashed to ensure it hasn't already been unlinked and marked for destruction by the release path. This aligns the locking pattern with recv_hdlc() and recv_disc().
CVE-2026-64029 1 Linux 1 Linux Kernel 2026-07-22 7.8 High
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Serialize UMP output teardown with event_input seq_ump_process_event() borrows client->out_rfile.output without synchronizing with the first-open and last-close transition in seq_ump_client_open() and seq_ump_client_close(). The last output unuse can therefore drop opened[STR_OUT] to zero and release the rawmidi file while an in-flight event_input callback is still inside snd_rawmidi_kernel_write(). That leaves the rawmidi substream runtime exposed to teardown before the write path has taken its own buffer reference. Add a per-client rwlock for the event_input-visible output file. Publish a newly opened output file under the write side, and hold the read side from the output lookup through snd_rawmidi_kernel_write(). The last output close copies and clears the visible output file under the write side, then drops the lock and releases the saved rawmidi file. Use IRQ-safe rwlock guards because event_input can also be reached from atomic sequencer delivery. The buggy scenario involves two paths, with each column showing the order within that path: path A label: event_input path path B label: last unuse path 1. seq_ump_process_event() reads 1. seq_ump_client_close() client->out_rfile.output. drops opened[STR_OUT] to zero. 2. snd_rawmidi_kernel_write1() 2. snd_rawmidi_kernel_release() has not yet pinned runtime. closes the output file. 3. The writer continues using 3. close_substream() frees the borrowed substream. substream->runtime. This keeps the output substream and runtime alive for the full event_input write while keeping rawmidi release outside the rwlock. KASAN reproduced this as a slab-use-after-free in snd_rawmidi_kernel_write1(), with allocation through seq_ump_use()/snd_seq_port_connect() and free through seq_ump_unuse()/snd_seq_port_disconnect(). Validation reproduced this kernel report: KASAN slab-use-after-free in snd_rawmidi_kernel_write1+0x9d/0x400 RIP: 0033:0x7f5528af837f Read of size 8 Call trace: dump_stack_lvl+0x73/0xb0 (?:?) print_report+0xd1/0x650 (?:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x1a7/0x340 (?:?) kasan_complete_mode_report_info+0x64/0x200 (?:?) kasan_report+0xf7/0x130 (?:?) snd_rawmidi_kernel_write1+0x9d/0x400 (?:?) __asan_load8+0x82/0xb0 (?:?) update_stack_state+0x1ef/0x2d0 (?:?) snd_rawmidi_kernel_write+0x1a/0x20 (?:?) seq_ump_process_event+0xd4/0x120 (sound/core/seq/seq_ump_client.c:82) __snd_seq_deliver_single_event+0x8a/0xe0 (?:?) snd_seq_deliver_from_ump+0x2b2/0xd60 (?:?) lock_acquire+0x14e/0x2e0 (?:?) find_held_lock+0x31/0x90 (?:?) snd_seq_port_use_ptr+0xa6/0xe0 (?:?) __kasan_check_write+0x18/0x20 (?:?) do_raw_read_unlock+0x32/0xa0 (?:?) _raw_read_unlock+0x26/0x50 (?:?) snd_seq_deliver_single_event+0x45c/0x4b0 (?:?) snd_seq_deliver_event+0x10d/0x1b0 (?:?) snd_seq_client_enqueue_event+0x192/0x240 (?:?) snd_seq_write+0x2cd/0x450 (?:?) apparmor_file_permission+0x20/0x30 (?:?) security_file_permission+0x51/0x60 (?:?) vfs_write+0x1ce/0x850 (?:?) __fget_files+0x12b/0x220 (?:?) lock_release+0xc8/0x2a0 (?:?) __rcu_read_unlock+0x74/0x2d0 (?:?) __fget_files+0x135/0x220 (?:?) ksys_write+0x15a/0x180 (?:?) rcu_is_watching+0x24/0x60 (?:?) __x64_sys_write+0x46/0x60 (?:?) x64_sys_call+0x7d/0x20d0 (?:?) do_syscall_64+0xc1/0x360 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)
CVE-2026-63944 1 Linux 1 Linux Kernel 2026-07-21 8.8 High
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync hci_le_create_cis_sync() dereferences conn->conn_timeout after releasing both rcu_read_lock() and hci_dev_lock(hdev). The conn pointer was obtained from an RCU-protected iteration over hdev->conn_hash.list and is not valid once these locks are dropped. A concurrent disconnect can free the hci_conn between the unlock and the dereference, causing a use-after-free read. The cancellation mechanism in hci_conn_del() cannot prevent this because hci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL: hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL); While hci_conn_del() dequeues with data=conn: hci_cmd_sync_dequeue(hdev, NULL, conn, NULL); Since NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never matches, and the pending work item is not cancelled. Fix this by saving conn->conn_timeout into a local variable while the locks are still held, so the stale conn pointer is never dereferenced after unlock. This is the same class of bug as the one fixed by commit 035c25007c9e ("Bluetooth: hci_sync: Fix UAF on le_read_features_complete") which addressed the identical pattern in a different function. This vulnerability was identified using 0sec.ai, an open-source automated security auditing platform (https://github.com/0sec-labs).
CVE-2026-53341 1 Linux 1 Linux Kernel 2026-07-18 7.8 High
In the Linux kernel, the following vulnerability has been resolved: fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() may_decode_fh() accesses mount::mnt_ns without holding any locks; that means the mount can concurrently be unmounted, and the mnt_namespace can concurrently be freed after an RCU grace period. This race can happens as follows, assuming that the mount point was created by open_tree(..., OPEN_TREE_CLONE): thread 1 thread 2 RCU __do_sys_open_by_handle_at do_handle_open handle_to_path may_decode_fh is_mounted [mount::mnt_ns access] [mount::mnt_ns access] __do_sys_close fput_close_sync __fput dissolve_on_fput umount_tree class_namespace_excl_destructor namespace_unlock free_mnt_ns mnt_ns_tree_remove call_rcu(mnt_ns_release_rcu) mnt_ns_release_rcu mnt_ns_release kfree [mnt_namespace::user_ns access] **UAF** Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like in __prepend_path(). Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE() for writers that can race with lockless readers. This bug is unreachable unless one of the following is set: - CONFIG_PREEMPTION - CONFIG_RCU_STRICT_GRACE_PERIOD because it requires an RCU grace period to happen during a syscall without an explicit preemption. This doesn't seem to have interesting security impact; worst-case, it could leak the result of an integer comparison to userspace (from the level check in cap_capable()), cause an endless loop, or crash the kernel by dereferencing an invalid address.