CVE-2026-43103 net: lapbether: handle NETDEV_PRE_TYPE_CHANGE
A missing event handler in the Linux kernel's lapbether driver allows bonding drivers to violate device type expectations, potentially causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43103?
CVE-2026-43103 is a medium-severity denial of service vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: lapbether: handle NETDEV_PRE_TYPE_CHANGE
lapbeth_data_transmit() expects the underlying device type to be ARPHRD_ETHER.
Returning NOTIFY_BAD from lapbeth_device_event() makes sure bonding driver can not break this expectation.
Which versions are affected by CVE-2026-43103?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43103?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-43103 being exploited?
There is no known exploitation of CVE-2026-43103 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43103, DEBIAN-CVE-2026-43103, GHSA-vmcc-hwvc-gq3r, ROOT-OS-DEBIAN-11-CVE-2026-43103, ROOT-OS-DEBIAN-12-CVE-2026-43103, ROOT-OS-UBUNTU-2204-CVE-2026-43103 and 2 more.