Linux Kernel up to 6.18.18/6.19.8 net/core/dev.c netif_napi_del privilege escalation

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.18/6.19.8. It has been rated as problematic. This vulnerability affects the function netif_napi_del of the file net/core/dev.c. Performing a manipulation results in an unknown weakness. This vulnerability is identified as CVE-2026-43479. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Linux Kernel up to 6.18.18/6.19.8. This affects the function netif_napi_del of the file net/core/dev.c. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net: usb: lan78xx: fix WARN in __netif_napi_del_locked on disconnect Remove redundant netif_napi_del() call from disconnect path. A WARN may be triggered in __netif_napi_del_locked() during USB device disconnect: WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350 This happens because netif_napi_del() is called in the disconnect path while NAPI is still enabled. However, it is not necessary to call netif_napi_del() explicitly, since unregister_netdev() will handle NAPI teardown automatically and safely. Removing the redundant call avoids triggering the warning. Full trace: lan78xx 1-1:1.0 enu1: Failed to read register index 0x000000c4. ret = -ENODEV lan78xx 1-1:1.0 enu1: Failed to set MAC down with error -ENODEV lan78xx 1-1:1.0 enu1: Link is Down lan78xx 1-1:1.0 enu1: Failed to read register index 0x00000120. ret = -ENODEV ------------[ cut here ]------------ WARNING: CPU: 0 PID: 11 at net/core/dev.c:7417 __netif_napi_del_locked+0x2b4/0x350 Modules linked in: flexcan can_dev fuse CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.0-rc2-00624-ge926949dab03 #9 PREEMPT Hardware name: SKOV IMX8MP CPU revC - bd500 (DT) Workqueue: usb_hub_wq hub_event pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __netif_napi_del_locked+0x2b4/0x350 lr : __netif_napi_del_locked+0x7c/0x350 sp : ffffffc085b673c0 x29: ffffffc085b673c0 x28: ffffff800b7f2000 x27: ffffff800b7f20d8 x26: ffffff80110bcf58 x25: ffffff80110bd978 x24: 1ffffff0022179eb x23: ffffff80110bc000 x22: ffffff800b7f5000 x21: ffffff80110bc000 x20: ffffff80110bcf38 x19: ffffff80110bcf28 x18: dfffffc000000000 x17: ffffffc081578940 x16: ffffffc08284cee0 x15: 0000000000000028 x14: 0000000000000006 x13: 0000000000040000 x12: ffffffb0022179e8 x11: 1ffffff0022179e7 x10: ffffffb0022179e7 x9 : dfffffc000000000 x8 : 0000004ffdde8619 x7 : ffffff80110bcf3f x6 : 0000000000000001 x5 : ffffff80110bcf38 x4 : ffffff80110bcf38 x3 : 0000000000000000 x2 : 0000000000000000 x1 : 1ffffff0022179e7 x0 : 0000000000000000 Call trace: __netif_napi_del_locked+0x2b4/0x350 (P) lan78xx_disconnect+0xf4/0x360 usb_unbind_interface+0x158/0x718 device_remove+0x100/0x150 device_release_driver_internal+0x308/0x478 device_release_driver+0x1c/0x30 bus_remove_device+0x1a8/0x368 device_del+0x2e0/0x7b0 usb_disable_device+0x244/0x540 usb_disconnect+0x220/0x758 hub_event+0x105c/0x35e0 process_one_work+0x760/0x17b0 worker_thread+0x768/0xce8 kthread+0x3bc/0x690 ret_from_fork+0x10/0x20 irq event stamp: 211604 hardirqs last enabled at (211603): [<ffffffc0828cc9ec>] _raw_spin_unlock_irqrestore+0x84/0x98 hardirqs last disabled at (211604): [<ffffffc0828a9a84>] el1_dbg+0x24/0x80 softirqs last enabled at (211296): [<ffffffc080095f10>] handle_softirqs+0x820/0xbc8 softirqs last disabled at (210993): [<ffffffc080010288>] __do_softirq+0x18/0x20 ---[ end trace 0000000000000000 ]--- lan78xx 1-1:1.0 enu1: failed to kill vid 0081/0

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-43479 since 05/01/2026. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/23/2026).

Upgrading to version 6.18.19 or 6.19.9 eliminates this vulnerability. Applying the patch 20ce2bd1c1848414c5d3520d301ed3f5751ed634/395a8b903738511f536c97c427e15ef038e1a11c/312c816c6bc30342bc30dca0d6db617ab4d3ae4e is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1531). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 6.19.7
• 6.19.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

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Entryinfo

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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