CVE-2026-90166 smb/server: fix null-ptr-deref in ksmbd_ipc_tree_connect_request()

Not scored Published 17 Sep 2026 Updated 21 Oct 2026

A null pointer dereference in the Linux kernel's ksmbd SMB server allows a low-privileged user to cause a denial of service.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-90166?

CVE-2026-90166 is a vulnerability in Linux, published on 17 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

smb/server: fix null-ptr-deref in ksmbd_ipc_tree_connect_request()

See the procedure below:

ksmbd_tree_conn_connect ksmbd_share_config_get share->name = kstrdup() // fail if (!test_share_config_flag(share, KSMBD_SHARE_FLAG_PIPE)) // false // do not check `share->name` ksmbd_ipc_tree_connect_request strlen(share->name) // null-ptr-deref

Which versions are affected by CVE-2026-90166?

How do I fix CVE-2026-90166?

Apply the vendor's patch.

Is CVE-2026-90166 being exploited?

There is no known exploitation of CVE-2026-90166 in the wild and no public exploit code.

Sources

Also known as AZL-102218, BELL-CVE-2026-90166, DEBIAN-CVE-2026-90166, GHSA-72gq-5j57-9667, UBUNTU-CVE-2026-90166.