CVE-2026-98574
Received Received - Intake

Linux kernel Net Device Driver Use-After-Free

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: bcmgenet: stop Tx NAPI before disabling the queues bcmgenet_netif_stop() and the Wake-on-LAN branch of bcmgenet_suspend() both disable the Tx queues first and stop Tx NAPI several steps later. A completion in flight calls netif_tx_wake_queue() in between, and nothing stops the queue again, so a transmit can reach the rings after they have been freed. Close is safe because dev_deactivate_many() stops the qdisc first. bcmgenet_suspend() does not, so stop Tx NAPI before the queues on both paths. KASAN on a Raspberry Pi CM4, driven from an MTU change because suspend freezes user space before the callback runs: BUG: KASAN: use-after-free in bcmgenet_xmit+0x17f8/0x2258 Write of size 8 at addr ffffff8055844a68 by task ksoftirqd/0/14 bcmgenet_xmit+0x17f8/0x2258 dev_hard_start_xmit+0x13c/0x588 sch_direct_xmit+0x108/0x340 __dev_queue_xmit+0x1190/0x3848

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98574
EUVD
EUVD-2026-103619

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
Linux Linux 254f3239dd070e469f45c3ca8b6ac38e47d6c730
Linux Linux 254f3239dd070e469f45c3ca8b6ac38e47d6c730
Linux Linux 254f3239dd070e469f45c3ca8b6ac38e47d6c730
Linux Linux 6.15

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the bcmgenet network driver. The issue occurs when the Tx queues are disabled before stopping the Tx NAPI, allowing a transmit operation to access memory after it has been freed. This leads to a use-after-free error, which can cause system crashes or instability.

Detection Guidance

This vulnerability is specific to the Linux kernel's bcmgenet driver and may not have direct detection commands. Monitor kernel logs for use-after-free errors or crashes related to bcmgenet_xmit. Check for KASAN reports or system hangs during network operations.

Impact Analysis

This vulnerability can cause system crashes, data corruption, or denial of service by triggering a use-after-free error in the Linux kernel. It may lead to kernel panics or unexpected behavior, especially on affected systems like Raspberry Pi CM4.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this issue. If immediate patching is not possible, disable the bcmgenet driver or network interfaces using it until the kernel is updated.

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