Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:L) | Local access needed |
| Attack complexity (AC:L) | Low complexity |
| Privileges required (PR:L) | Low privileges required |
| User interaction (UI:N) | No user interaction |
| Scope (S:U) | Scope unchanged |
| Confidentiality (C:H) | High confidentiality impact |
| Integrity (I:N) | No integrity impact |
| Availability (A:H) | High availability impact |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
About Linux Kernel
CVE-2025-71201 affects Linux Kernel, a product from Linux. Before acting, confirm where Linux Kernel runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: In the Linux kernel, the following vulnerability has been resolved: netfs: Fix early read unlock of page with EOF in middle The read result collection for buffered reads seems to run ahead of the completion of subrequests under some circumstances, as can be seen in the following log snippet: 9p_client_res: client 18446612686390831168 response P9_TREAD tag 0 err 0 ... netfs_sreq: R=00001b55[1] DOWN TERM f=192 s=0 5fb2/5fb2 s=5 e=0 ... netfs_collect_folio: R=00001b55 ix=00004 r=4000-5000 t=4000/5fb2 netfs_folio: i=157f3 ix=00004-00004 read-done netfs_folio: i=157f3 ix=00004-00004 read-unlock netfs_collect_folio: R=00001b55 ix=00005 r=5000-5fb2 t=5000/5fb2 netfs_folio: i=157f3 ix=00005-00005 read-done netfs_folio: i=157f3 ix=00005-00005 read-unlock ... netfs_collect_stream: R=00001b55[0:] cto=5fb2 frn=ffffffff netfs_collect_state: R=00001b55 col=5fb2 cln=6000 n=c netfs_collect_stream: R=00001b55[0:] cto=5fb2 frn=ffffffff netfs_collect_state: R=00001b55 col=5fb2 cln=6000 n=8 ... netfs_sreq: R=00001b55[2] ZERO SUBMT f=000 s=5fb2 0/4e s=0 e=0 netfs_sreq: R=00001b55[2] ZERO TERM f=102 s=5fb2 4e/4e s=5 e=0 The 'cto=5fb2' indicates the collected file pos we've collected results to so far - but we still have 0x4e more bytes to go - so we shouldn't have collected folio ix=00005 yet. The 'ZERO' subreq that clears the tail happens after we unlock the folio, allowing the application to see the uncleared tail through mmap. The problem is that netfs_read_unlock_folios() will unlock a folio in which the amount of read results collected hits EOF position - but the ZERO subreq lies beyond that and so happens after. Fix this by changing the end check to always be the end of the folio and never the end of the file. In the future, I should look at clearing to the end of the folio here rather than adding a ZERO subreq to do this. On the other hand, the ZERO subreq can run in parallel with an async READ subreq. Further, the ZERO subreq may still be necessary to, say, handle extents in a ceph file that don't have any backing store and are thus implicitly all zeros. This can be reproduced by creating a file, the size of which doesn't align to a page boundary, e.g. 24998 (0x5fb2) bytes and then doing something like: xfs_io -c "mmap -r 0 0x6000" -c "madvise -d 0 0x6000" \ -c "mread -v 0 0x6000" /xfstest.test/x The last 0x4e bytes should all be 00, but if the tail hasn't been cleared yet, you may see rubbish there. This can be reproduced with kafs by modifying the kernel to disable the call to netfs_read_subreq_progress() and to stop afs_issue_read() from doing the async call for NETFS_READAHEAD. Reproduction can be made easier by inserting an mdelay(100) in netfs_issue_read() for the ZERO-subreq case. AFS and CIFS are normally unlikely to show this as they dispatch READ ops asynchronously, which allows the ZERO-subreq to finish first. 9P's READ op is completely synchronous, so the ZERO-subreq will always happen after. It isn't seen all the time, though, because the collection may be done in a worker thread.
The weakness class is Out of Bounds Read. The program reads memory past the end of a buffer, leaking data or crashing.
Based on its CVSS vector, the flaw needs local or adjacent access, needs some level of access, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Linux Kernel |
| Affected versions | Linux Kernel from 6.14 before 6.18.6; Linux Kernel 6.19 |
| Published | Feb 14, 2026 |
| Last modified | Jul 30, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
How to detect it
- Inventory every instance of Linux Kernel and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Linux Kernel named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Linux Kernel to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
- CWE-125: Out of Bounds Read More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
In the Linux kernel, the following vulnerability has been resolved: cgroup: Avoid iteration of dying tasks with zero refcount The commit 260fbcb92bbea ("cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free()") extended the lifetime of tasks on the dying_tasks list. The iterators have provision to go through dying_tasks because of dying threadgroup leaders or explicit CSS_TASK_ITER_WITH_DEAD, however, it was expected that such tasks can obtain a new reference (that is possible before cgroup_task_release()/put_task_struct_rcu_user()). The tasks after cgroup_task_release() and before cgroup_task_free() are subject to race when they may or may not have ->usage count > 0. The race window is between css_task_iter_next() invocations when css_set_lock is released and we may arrive at a new ->task_pos. The iterator should not attempt to resurrect tasks whose ->usage count dropped to zero. (When that happens, __put_task_struct_rcu_cb() is already imminent and the returned task_struct would could be used after free.) As for the fix, we cannot simply check the signal->live count of a task on the dying list because that won't distinguish regular zombies waiting to be reaped from RCU remnant tasks that are going to be free'd. Therefore add an extra check to rule out ->usage==0 tasks from any iteration. The repeat: loop in css_task_iter_advance() doesn't consider ->usage count, so add a new loop to css_task_iter_next() to skip de-used tasks on the dying_list. Rough illustration of the possible race R (reader of cgroup.procs) T (thread) L (group leader) --------------------------------- -------------------------------- -------------------------------- L exits, signal->live > 0 cgroup_task_dead(L) css_set_skip_task_iters() // skips only cset->tasks list_add_tail(&L->cg_list, &cset->dying_tasks) css_task_iter_next() take css_set_lock css_task_iter_advance() leader && signal->live != 0 => it->task_pos = &L->cg_list release css_set_lock T exits --signal->live == 0 cgroup_task_dead(T) // css_set_lock release_task(T) cgroup_task_release(T) release_task(L) // zap_leader cgroup_task_release(L) put_task_struct_rcu_user(L) ...RCU... put_task_struct(L) L->usage = 0 /* L still on dying_tasks */ ...RCU... __put_task_struct(L) css_task_iter_next() // another iteration take css_set_lock it->task_pos = &L->cg_list get_task_struct(L) => addition on 0 drop css_set_lock cgroup_task_free(L) css_set_skip_task_iters() // dying skip comes too late free_task(L) cgroup_procs_show() task_pid_vnr(L)
In the Linux kernel, the following vulnerability has been resolved: ntfs: bound $AttrDef table walk to the loaded table size ntfs_attr_find_in_attrdef() walks the in-memory $AttrDef table, but the loop condition bounds only the start of each entry, not the whole entry: for (ad = vol->attrdef; (u8 *)ad - (u8 *)vol->attrdef < vol->attrdef_size && ad->type; ++ad) struct attr_def is 160 bytes; the guard reads ad->type at offset 128 and the loop body reads further fields. vol->attrdef is kvzalloc(i_size), where i_size is the on-disk $AttrDef data size, checked in load_and_init_attrdef() only as 0 < i_size <= 0x7fffffff. A volume whose $AttrDef data size is smaller than one entry (e.g. 120 bytes) makes the read of ad->type run past the allocation. Creating a file reaches this through ntfs_attr_size_bounds_check() and reads out of bounds: BUG: KASAN: slab-out-of-bounds in ntfs_attr_find_in_attrdef+0x66/0xa0 Read of size 4 at addr ffff888005833280 by task init/1 ntfs_attr_find_in_attrdef ntfs_attr_size_bounds_check ntfs_attr_can_be_non_resident ntfs_attr_add Require the whole entry to lie within attrdef_size in the loop guard, and reject at mount a $AttrDef too small to hold one attr_def entry.
In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: fix disconnect UAF in client teardown usbio_disconnect() walks usbio->cli_list in reverse and uninitializes each auxiliary device. auxiliary_device_uninit() drops the device reference, and for an unbound child that can run usbio_auxdev_release() and free the containing struct usbio_client. list_for_each_entry_reverse() advances after the loop body by reading client->link.prev. If the current client is freed by auxiliary_device_uninit(), the iterator dereferences freed memory. Use list_for_each_entry_safe_reverse() so the previous client is cached before the body can drop the final reference. This preserves reverse teardown order while keeping the next iterator cursor independent of the current client's lifetime. Validation reproduced this kernel report: BUG: KASAN: slab-use-after-free in usbio_disconnect+0x12e/0x150 Call Trace: <TASK> dump_stack_lvl+0x66/0xa0 print_report+0xce/0x630 ? usbio_disconnect+0x12e/0x150 ? srso_alias_return_thunk+0x5/0xfbef5 ? __virt_addr_valid+0x188/0x320 ? usbio_disconnect+0x12e/0x150 kasan_report+0xe0/0x110 ? usbio_disconnect+0x12e/0x150 usbio_disconnect+0x12e/0x150 usb_unbind_interface+0xf3/0x400 really_probe+0x316/0x660 __driver_probe_device+0x106/0x240 driver_probe_device+0x4a/0x110 __device_attach_driver+0xf1/0x1a0 ? __pfx___device_attach_driver+0x10/0x10 bus_for_each_drv+0xf9/0x160 ? __pfx_bus_for_each_drv+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? trace_hardirqs_on+0x18/0x130 ? srso_alias_return_thunk+0x5/0xfbef5 ? _raw_spin_unlock_irqrestore+0x44/0x60 __device_attach+0x133/0x2a0 ? __pfx___device_attach+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_raw_spin_unlock+0x9a/0x100 ? srso_alias_return_thunk+0x5/0xfbef5 device_initial_probe+0x55/0x70 bus_probe_device+0x4a/0xd0 device_add+0x9b9/0xc10 ? __pfx_device_add+0x10/0x10 ? _raw_spin_unlock_irqrestore+0x44/0x60 ? srso_alias_return_thunk+0x5/0xfbef5 ? lockdep_hardirqs_on_prepare+0xea/0x1a0 ? srso_alias_return_thunk+0x5/0xfbef5 ? usb_enable_lpm+0x3c/0x260 usb_set_configuration+0xb64/0xf20 usb_generic_driver_probe+0x5f/0x90 usb_probe_device+0x71/0x1b0 really_probe+0x46b/0x660 __driver_probe_device+0x106/0x240 driver_probe_device+0x4a/0x110 __device_attach_driver+0xf1/0x1a0 ? __pfx___device_attach_driver+0x10/0x10 bus_for_each_drv+0xf9/0x160 ? __pfx_bus_for_each_drv+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? trace_hardirqs_on+0x18/0x130 ? srso_alias_return_thunk+0x5/0xfbef5 ? _raw_spin_unlock_irqrestore+0x44/0x60 __device_attach+0x133/0x2a0 ? __pfx___device_attach+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? do_raw_spin_unlock+0x9a/0x100 ? srso_alias_return_thunk+0x5/0xfbef5 device_initial_probe+0x55/0x70 bus_probe_device+0x4a/0xd0 device_add+0x9b9/0xc10 ? __pfx_device_add+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? add_device_randomness+0xb7/0xf0 usb_new_device+0x492/0x870 hub_event+0x1b10/0x29c0 ? __pfx_hub_event+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_acquire+0x187/0x300 ? process_one_work+0x475/0xb90 ? srso_alias_return_thunk+0x5/0xfbef5 ? lock_release+0xc8/0x290 ? srso_alias_return_thunk+0x5/0xfbef5 process_one_work+0x4d7/0xb90 ? __pfx_process_one_work+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? srso_alias_return_thunk+0x5/0xfbef5 ? __list_add_valid_or_report+0x37/0xf0 ? __pfx_hub_event+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 worker_thread+0x2d8/0x570 ? __pfx_worker_thread+0x10/0x10 kthread+0x1ad/0x1f0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x3c9/0x540 ? __pfx_ret_from_fork+0x10/0x10 ? srso_alias_return_thunk+0x5/0xfbef5 ? __switch_to+0x2e9/0x730 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>
In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix heap buffer overflow in rtw_cfg80211_set_wpa_ie() supplicant_ie is a 256-byte array in struct security_priv. The WPA and WPA2 IE copy paths use: memcpy(padapter->securitypriv.supplicant_ie, &pwpa[0], wpa_ielen + 2); where wpa_ielen is the raw IE length field (u8, 0-255). When a local user supplies a connect request via nl80211 with a crafted WPA IE of length 255, wpa_ielen + 2 equals 257, overflowing the 256-byte buffer by one byte into the adjacent last_mic_err_time field. rtw_parse_wpa_ie() does not prevent this: its length consistency check compares *(wpa_ie+1) against (u8)(wpa_ie_len-2), which is (u8)(255) == 255 when wpa_ie_len = 257, so the check passes silently. Add explicit bounds checks for both the WPA and WPA2 paths before the memcpy, rejecting any IE whose total size (wpa_ielen + 2) exceeds the supplicant_ie buffer.
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: Fix UAF of hci_conn_params in add_device_complete add_device_complete() runs from the hci_cmd_sync_work kworker, which holds only hci_req_sync_lock and *not* hci_dev_lock. It calls hci_conn_params_lookup() and then dereferences the returned object (params->flags) without taking hci_dev_lock: params = hci_conn_params_lookup(hdev, &cp->addr.bdaddr, le_addr_type(cp->addr.type)); ... device_flags_changed(NULL, hdev, &cp->addr.bdaddr, cp->addr.type, hdev->conn_flags, params ? params->flags : 0); hci_conn_params_lookup() walks hdev->le_conn_params and is documented to require hdev->lock. A concurrent MGMT_OP_REMOVE_DEVICE (remove_device()), which does run under hci_dev_lock, can call hci_conn_params_free() to list_del() and kfree() the very object the lookup returned, so the subsequent params->flags read touches freed memory [0]. Hold hci_dev_lock() across the hci_conn_params_lookup() and the read of params->flags (and the matching event emission) so the lookup result cannot be freed by a concurrent remove_device() before it is used, honouring the locking contract of hci_conn_params_lookup(). [0]: (trailing page/memory-state dump trimmed) BUG: KASAN: slab-use-after-free in add_device_complete+0x358/0x3d8 net/bluetooth/mgmt.c:7671 Read of size 1 at addr ffff000017ab26c1 by task kworker/u9:8/388 CPU: 1 UID: 0 PID: 388 Comm: kworker/u9:8 Not tainted 7.0.11 #20 PREEMPT Hardware name: linux,dummy-virt (DT) Workqueue: hci0 hci_cmd_sync_work Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xb4/0xd4 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x118/0x5d8 mm/kasan/report.c:482 kasan_report+0xb0/0xf4 mm/kasan/report.c:595 __asan_report_load1_noabort+0x20/0x2c mm/kasan/report_generic.c:378 add_device_complete+0x358/0x3d8 net/bluetooth/mgmt.c:7671 hci_cmd_sync_work+0x14c/0x240 net/bluetooth/hci_sync.c:334 process_one_work+0x628/0xd38 kernel/workqueue.c:3289 process_scheduled_works kernel/workqueue.c:3372 [inline] worker_thread+0x7a8/0xac0 kernel/workqueue.c:3453 kthread+0x39c/0x444 kernel/kthread.c:436 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 Allocated by task 3401: kasan_save_stack+0x3c/0x64 mm/kasan/common.c:57 kasan_save_track+0x20/0x3c mm/kasan/common.c:78 kasan_save_alloc_info+0x40/0x54 mm/kasan/generic.c:570 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xd4/0xd8 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x1b0/0x458 mm/slub.c:5385 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] hci_conn_params_add+0x10c/0x4b0 net/bluetooth/hci_core.c:2279 hci_conn_params_set net/bluetooth/mgmt.c:5162 [inline] add_device+0x5b4/0xa54 net/bluetooth/mgmt.c:7755 hci_mgmt_cmd net/bluetooth/hci_sock.c:1721 [inline] hci_sock_sendmsg+0x10b4/0x1dd0 net/bluetooth/hci_sock.c:1841 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0xe0/0x128 net/socket.c:742 sock_write_iter+0x250/0x390 net/socket.c:1195 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x66c/0xab0 fs/read_write.c:688 ksys_write+0x1fc/0x24c fs/read_write.c:740 __do_sys_write fs/read_write.c:751 [inline] __se_sys_write fs/read_write.c:748 [inline] __arm64_sys_write+0x70/0xa4 fs/read_write.c:748 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x84/0x2a8 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xe4/0x294 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x44/0x5c arch/arm64/kernel/syscall.c:151 el0_svc+0x38/0xac arch/arm64/kernel/entry-common.c:724 el0t_64_sync_handler+0xa0/0xe4 arch/arm64/kernel/entry-common.c:743 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596 Freed by task 3740: kasan_save_stack+0x3c/0x64 ---truncated---
In the Linux kernel, the following vulnerability has been resolved: netpoll: fix a use-after-free on shutdown path There is a use-after-free error on netpoll, which is clearly detected by KASAN. BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x3b/0x80 Read of size 1 at addr ... by task kworker/9:1 Workqueue: events queue_process Call Trace: skb_dequeue+0x1e/0xb0 queue_process+0x2c/0x600 process_scheduled_works+0x4b6/0x850 worker_thread+0x414/0x5a0 Allocated by task 242: __netpoll_setup+0x201/0x4a0 netpoll_setup+0x249/0x550 enabled_store+0x32f/0x380 Freed by task 0: kfree+0x1b7/0x540 rcu_core+0x3f8/0x7a0 The problem happens when there is a pending TX worker running in parallel with the cleanup path. This is what happens on netpoll shutdown path: 1) __netpoll_cleanup() is called 2) set dev->npinfo to NULL 3) call_rcu() with rcu_cleanup_netpoll_info() 3.1) rcu_cleanup_netpoll_info() tries to cancel all workers with cancel_delayed_work(), but doesn't wait for the worker to finish 4) and kfree(npinfo); Because 3.1) doesn't really cancel the work, as the comment says "we can't call cancel_delayed_work_sync here, as we are in softirq", the TX worker can run after 4). Tl;DR: queue_process() is not an RCU reader, it reaches npinfo through the work item via container_of(). Use disable_delayed_work_sync() to ensure the worker is completely stopped and prevent any future re-arming attempts. Once npinfo is set to NULL, senders will bail out and not queue new work. The disable flag ensures any in-flight re-arming attempts also fail silently. In the future, we can do the cleanup inline here without needing the npinfo->rcu rcu_head, but that is net-next material.
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