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Linux Kernel CVE-2026-43479

| EUVDEUVD-2026-30015 MEDIUM
2026-05-13 Linux GHSA-xjxc-mpvc-4vhr
Linux Information Disclosure Red Hat Suse
5.5
CVSS 3.1 · NVD
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Severity by source

NVD PRIMARY
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.5 MEDIUM

Local vector confirmed; PR:L required as USB unbind via sysfs needs user session; no confidentiality or integrity impact per description.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
MEDIUM
qualitative
Red Hat
MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

5
Analysis Generated
Jun 26, 2026 - 22:31 vuln.today
CVSS changed
Jun 26, 2026 - 20:22 NVD
5.5 (MEDIUM)
Patch available
May 13, 2026 - 16:33 EUVD
CVE Published
May 13, 2026 - 15:08 nvd
MEDIUM 5.5
CVE Published
May 13, 2026 - 15:08 nvd
UNKNOWN (no severity yet)

DescriptionNVD

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

AnalysisAI

Kernel availability disruption in the Linux lan78xx USB-to-Ethernet driver allows a local user with low privileges to trigger a kernel WARN in __netif_napi_del_locked() by disconnecting an affected USB Ethernet adapter. The root cause is a redundant netif_napi_del() call in the driver's disconnect path while NAPI processing is still active, conflicting with the teardown that unregister_netdev() performs automatically. No public exploit exists and EPSS is 0.02% (4th percentile), indicating very low real-world exploitation interest; this is primarily a stability and denial-of-service concern on embedded and desktop Linux systems using the SMSC/Microchip LAN78xx adapter family.

Technical ContextAI

The lan78xx driver (net/usb/lan78xx) implements support for Microchip LAN7800 and LAN7850 USB 3.0 Gigabit Ethernet adapters. NAPI (New API) is the Linux kernel interrupt-mitigation subsystem used by network drivers to process receive packets in a polling loop rather than per-interrupt. During USB device disconnection, the driver's lan78xx_disconnect() routine incorrectly calls netif_napi_del() explicitly while NAPI is still in the enabled state; this triggers a kernel WARN_ON assertion at net/core/dev.c:7417 inside __netif_napi_del_locked() because the NAPI instance is not yet idle. The correct teardown sequence relies on unregister_netdev() to quiesce and remove NAPI contexts automatically and safely. The CWE field is listed as N/A by NVD, but this most closely resembles a double-free or improper cleanup ordering issue (analogous to CWE-672, Operation on a Resource After Expiration or Release). CPE strings confirm the affected product is cpe:2.3:a:linux:linux:*.

RemediationAI

Vendor-released patches are available across three stable kernel branches. Upgrade to Linux 6.18.19 (stable commit 312c816c6bc30342bc30dca0d6db617ab4d3ae4e, https://git.kernel.org/stable/c/312c816c6bc30342bc30dca0d6db617ab4d3ae4e), Linux 6.19.9 (stable commit 395a8b903738511f536c97c427e15ef038e1a11c, https://git.kernel.org/stable/c/395a8b903738511f536c97c427e15ef038e1a11c), or Linux 7.0 mainline (commit 20ce2bd1c1848414c5d3520d301ed3f5751ed634, https://git.kernel.org/stable/c/20ce2bd1c1848414c5d3520d301ed3f5751ed634). For systems that cannot be patched immediately, a targeted workaround is to blacklist the lan78xx kernel module (echo 'blacklist lan78xx' >> /etc/modprobe.d/blacklist.conf && modprobe -r lan78xx) - this disables LAN78xx USB Ethernet support entirely, which is acceptable only if no such adapters are in use. The WARN itself does not crash the kernel in most configurations, so the urgency for non-LAN78xx systems is zero.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Not-Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 Not-Affected

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CVE-2026-43479 vulnerability details – vuln.today
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