CVE-2026-98359 RDMA/core: Reject unregistering netdevs in ib_get_eth_speed
A missing state check in the Linux kernel RDMA core allows accessing unregistered network devices, potentially causing a null pointer dereference and system crash.
- 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-2026-98359?
CVE-2026-98359 is a high-severity vulnerability in Linux, published on 6 Oct 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:
RDMA/core: Reject unregistering netdevs in ib_get_eth_speed
ib_device_get_netdev() intentionally returns a referenced net_device even when it is unregistering, so matching and cleanup callers can still find the association. The reference keeps struct net_device allocated, but does not guarantee that the device remains operational.
ib_get_eth_speed() uses the returned device operationally by invoking its ethtool callback. Although that call is made under RTNL, the function does not verify the registration state first. An asynchronous RDMA port query can therefore call into a netdev after NETDEV_UNREGISTER and ndo_uninit have completed.
Check for NETREG_REGISTERED while holding RTNL and return -ENODEV for a device which is being unregistered. Keeping RTNL across the check and the ethtool operation prevents unregister from starting between them.
Keep the speed fallback and warning under RTNL as well, so the warning can safely read netdev->name. Drop the netdev reference before releasing RTNL once all accesses to the device are complete.
Which versions are affected by CVE-2026-98359?
How do I fix CVE-2026-98359?
Apply the vendor's patch.
Is CVE-2026-98359 being exploited?
There is no known exploitation of CVE-2026-98359 in the wild and no public exploit code.
Sources
Also known as AZL-106395, BELL-CVE-2026-98359, DEBIAN-CVE-2026-98359, GHSA-fhcv-jhv5-h3gg, UBUNTU-CVE-2026-98359.