CVE-2026-43234

What it is

In the Linux kernel, the following vulnerability has been resolved: team: avoid NETDEV_CHANGEMTU event when unregistering slave syzbot is reporting unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 3 ref_tracker: netdev@ffff88807dcf8618 has 1/2 users at __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline] netdev_hold include/linux/netdevice.h:4429 [inline] inetdev_init+0x201/0x4e0 net/ipv4/devinet.c:286 inetdev_event+0x251/0x1610 net/ipv4/devinet.c:1600 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_mtu net/core/dev.c:2318 [inline] netif_set_mtu_ext+0x5aa/0x800 net/core/dev.c:9886 netif_set_mtu+0xd7/0x1b0 net/core/dev.c:9907 dev_set_mtu+0x126/0x260 net/core/dev_api.c:248 team_port_del+0xb07/0xcb0 drivers/net/team/team_core.c:1333 team_del_slave drivers/net/team/team_core.c:1936 [inline] team_device_event+0x207/0x5b0 drivers/net/team/team_core.c:2929 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2281 [inline] call_netdevice_notifiers net/core/dev.c:2295 [inline] __dev_change_net_namespace+0xcb7/0x2050 net/core/dev.c:12592 do_setlink+0x2ce/0x4590 net/core/rtnetlink.c:3060 rtnl_changelink net/core/rtnetlink.c:3776 [inline] __rtnl_newlink net/core/rtnetlink.c:3935 [inline] rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4072 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6958 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 problem. Ido Schimmel found steps to reproduce ip link add name team1 type team ip link add name dummy1 mtu 1499 master team1 type dummy ip netns add ns1 ip link set dev dummy1 netns ns1 ip -n ns1 link del dev dummy1 and also found that the same issue was fixed in the bond driver in commit f51048c3e07b ("bonding: avoid NETDEV_CHANGEMTU event when unregistering slave"). Let's do similar thing for the team driver, with commit ad7c7b2172c3 ("net: hold netdev instance lock during sysfs operations") and commit 303a8487a657 ("net: s/__dev_set_mtu/__netif_set_mtu/") also applied.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-06 12:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-11-06 16:18 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 5.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-05-06 12:16 UTC

Last modified

2026-11-06 16:18 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Modified

Affected

• Linux Kernel < 6.18.16
• Linux Kernel < 6.19.6
• Linux Kernel 7.0

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-43234.md and follow it. Check whether this project is affected by CVE-2026-43234. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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