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Linux KernelOperating system · Linux

CVE-2023-53023

HIGH · 7.8 CVSS v3.1 Published 2025-03-27
Fix available
A fix is available. Upgrade to 4.14.305 / 4.19.272 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: net: nfc: Fix use-after-free in local_cleanup() Fix a use-after-free that occurs in kfree_skb() called from local_cleanup(). This could happen when killing nfc daemon (e.g. neard) after detaching an nfc device. When detaching an nfc device, local_cleanup() called from nfc_llcp_unregister_device() frees local->rx_pending and decreases local->ref by kref_put() in nfc_llcp_local_put(). In the terminating process, nfc daemon releases all sockets and it leads to decreasing local->ref. After the last release of local->ref, local_cleanup() called from local_release() frees local->rx_pending again, which leads to the bug. Setting local->rx_pending to NULL in local_cleanup() could prevent use-after-free when local_cleanup() is called twice. Found by a modified version of syzkaller. BUG: KASAN: use-after-free in kfree_skb() Call Trace: dump_stack_lvl (lib/dump_stack.c:106) print_address_description.constprop.0.cold (mm/kasan/report.c:306) kasan_check_range (mm/kasan/generic.c:189) kfree_skb (net/core/skbuff.c:955) local_cleanup (net/nfc/llcp_core.c:159) nfc_llcp_local_put.part.0 (net/nfc/llcp_core.c:172) nfc_llcp_local_put (net/nfc/llcp_core.c:181) llcp_sock_destruct (net/nfc/llcp_sock.c:959) __sk_destruct (net/core/sock.c:2133) sk_destruct (net/core/sock.c:2181) __sk_free (net/core/sock.c:2192) sk_free (net/core/sock.c:2203) llcp_sock_release (net/nfc/llcp_sock.c:646) __sock_release (net/socket.c:650) sock_close (net/socket.c:1365) __fput (fs/file_table.c:306) task_work_run (kernel/task_work.c:179) ptrace_notify (kernel/signal.c:2354) syscall_exit_to_user_mode_prepare (kernel/entry/common.c:278) syscall_exit_to_user_mode (kernel/entry/common.c:296) do_syscall_64 (arch/x86/entry/common.c:86) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:106) Allocated by task 4719: kasan_save_stack (mm/kasan/common.c:45) __kasan_slab_alloc (mm/kasan/common.c:325) slab_post_alloc_hook (mm/slab.h:766) kmem_cache_alloc_node (mm/slub.c:3497) __alloc_skb (net/core/skbuff.c:552) pn533_recv_response (drivers/nfc/pn533/usb.c:65) __usb_hcd_giveback_urb (drivers/usb/core/hcd.c:1671) usb_giveback_urb_bh (drivers/usb/core/hcd.c:1704) tasklet_action_common.isra.0 (kernel/softirq.c:797) __do_softirq (kernel/softirq.c:571) Freed by task 1901: kasan_save_stack (mm/kasan/common.c:45) kasan_set_track (mm/kasan/common.c:52) kasan_save_free_info (mm/kasan/genericdd.c:518) __kasan_slab_free (mm/kasan/common.c:236) kmem_cache_free (mm/slub.c:3809) kfree_skbmem (net/core/skbuff.c:874) kfree_skb (net/core/skbuff.c:931) local_cleanup (net/nfc/llcp_core.c:159) nfc_llcp_unregister_device (net/nfc/llcp_core.c:1617) nfc_unregister_device (net/nfc/core.c:1179) pn53x_unregister_nfc (drivers/nfc/pn533/pn533.c:2846) pn533_usb_disconnect (drivers/nfc/pn533/usb.c:579) usb_unbind_interface (drivers/usb/core/driver.c:458) device_release_driver_internal (drivers/base/dd.c:1279) bus_remove_device (drivers/base/bus.c:529) device_del (drivers/base/core.c:3665) usb_disable_device (drivers/usb/core/message.c:1420) usb_disconnect (drivers/usb/core.c:2261) hub_event (drivers/usb/core/hub.c:5833) process_one_work (arch/x86/include/asm/jump_label.h:27 include/linux/jump_label.h:212 include/trace/events/workqueue.h:108 kernel/workqueue.c:2281) worker_thread (include/linux/list.h:282 kernel/workqueue.c:2423) kthread (kernel/kthread.c:319) ret_from_fork (arch/x86/entry/entry_64.S:301)

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 3.9, < 4.14.305>= 4.15, < 4.19.272>= 4.20, < 5.4.231>= 5.5, < 5.10.166>= 5.11, < 5.15.91>= 5.16, < 6.1.9= 6.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.14.305 / 4.19.272 / 5.4.231 or later
Fixed in 4.14.3054.19.2725.4.231
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel >= 4.14.305, >= 4.19.272, >= 5.4.231, or >= 5.10.166 (or any later stable release)

  1. Upgrade the Linux kernel to a version that includes the fix: 4.14.305 or later for the 4.14.y branch, 4.19.272 or later for the 4.19.y branch, 5.4.231 or later for the 5.4.y branch, or 5.10.166 or later for the 5.10.y branch.
  2. After kernel upgrade, reboot the system to load the fixed kernel.
  3. For production systems, verify the fix is applied by checking that local_cleanup() in net/nfc/llcp_core.c sets rx_pending to NULL after kfree_skb().
Caveat Kernel upgrades may introduce compatibility issues with out-of-tree drivers or specific hardware firmware; ensure application compatibility before production deployment.

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2023-53023 in production — separate from our analysis above.

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