# CVE-2026-23192: linux: In the Linux kernel, the following vulnerability has been resolved:  linkwatch: use __dev_put() in callers to prevent...

CVE-2026-23192 is fixed in linux on 1 platform by DEBIAN-CVE-2026-23192 (version 6.18.10-1), released February 14, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-23192
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 14, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  linkwatch: use __dev_put() in callers to prevent UAF  After linkwatch_do_dev() calls __dev_put() to release the linkwatch reference, the device refcount may drop to 1. At this point, netdev_run_todo() can proceed (since linkwatch_sync_dev() sees an empty list and returns without blocking), wait for the refcount to become 1 via netdev_wait_allrefs_any(), and then free the device via kobject_put().  This creates a use-after-free when __linkwatch_run_queue() tries to call netdev_unlock_ops() on the already-freed device.  Note that adding netdev_lock_ops()/netdev_unlock_ops() pair in netdev_run_todo() before kobject_put() would not work, because netdev_lock_ops() is conditional - it only locks when netdev_need_ops_lock() returns true. If the device doesn't require ops_lock, linkwatch won't hold any lock, and netdev_run_todo() acquiring the lock won't provide synchronization.  Fix this by moving __dev_put() from linkwatch_do_dev() to its callers. The device reference logically pairs with de-listing the device, so it's reasonable for the caller that did the de-listing to release it. This allows placing __dev_put() after all device accesses are complete, preventing UAF.  The bug can be reproduced by adding mdelay(2000) after linkwatch_do_dev() in __linkwatch_run_queue(), then running:    ip tuntap add mode tun name tun_test   ip link set tun_test up   ip link set tun_test carrier off   ip link set tun_test carrier on   sleep 0.5   ip tuntap del mode tun name tun_test  KASAN report:   ==================================================================  BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]  BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]  BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245  Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123   CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014  Workqueue: events_unbound linkwatch_event  Call Trace:   <TASK>   __dump_stack lib/dump_stack.c:94 [inline]   dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120   print_address_description mm/kasan/report.c:378 [inline]   print_report+0x156/0x4c9 mm/kasan/report.c:482   kasan_report+0xdf/0x1a0 mm/kasan/report.c:595   netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]   netdev_unlock_ops include/net/netdev_lock.h:47 [inline]   __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245   linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304   process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257   process_scheduled_works kernel/workqueue.c:3340 [inline]   worker_thread+0x5da/0xe40 kernel/workqueue.c:3421   kthread+0x3b3/0x730 kernel/kthread.c:463   ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246   </TASK>  ==================================================================

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.18.10-1 | [DEBIAN-CVE-2026-23192](https://patchblox.com/security/data/fix/linux/debian-cve-2026-23192.md) | Feb 14, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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