CVE-2026-90164 smb/server: abort initialization when proc setup fails
A null pointer dereference in the Linux kernel SMB server can cause a denial of service when proc setup fails during initialization.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90164?
CVE-2026-90164 is a vulnerability in Linux, published on 17 Sep 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:
smb/server: abort initialization when proc setup fails
ksmbd_server_init() calls ksmbd_proc_init() before creating the remaining proc entries and server subsystems. ksmbd_proc_init() tears down partial state on a procfs or percpu_counter allocation failure, but returns void, so ksmbd_server_init() continues as if the counters were usable.
Once userspace starts the server, server_ctrl_handle_init() calls ksmbd_proc_reset(), which reaches percpu_counter_set() with a NULL per-CPU counters pointer on SMP systems. The later ksmbd_proc_create() calls also receive a NULL parent and may create entries in the /proc root; ksmbd_proc_cleanup() cannot remove those entries because ksmbd_proc_fs is NULL.
Which versions are affected by CVE-2026-90164?
How do I fix CVE-2026-90164?
Apply the vendor's patch.
Is CVE-2026-90164 being exploited?
There is no known exploitation of CVE-2026-90164 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-90164, GHSA-6gqw-gw67-f4rg, UBUNTU-CVE-2026-90164.