CVE-2026-22995 ublk: fix use-after-free in ublk_partition_scan_work
A race condition in the Linux kernel ublk driver allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.
- 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-2026-22995?
CVE-2026-22995 is a high-severity use after free vulnerability in Linux kernel, published on 23 Jan 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:
ublk: fix use-after-free in ublk_partition_scan_work
A race condition exists between the async partition scan work and device teardown that can lead to a use-after-free of ub->ub_disk:
1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk() 2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does: - del_gendisk(ub->ub_disk) - ublk_detach_disk() sets ub->ub_disk = NULL - put_disk() which may free the disk 3. The worker ublk_partition_scan_work() then dereferences ub->ub_disk leading to UAF
Fix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold a reference to the disk during the partition scan. The spinlock in ublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker either gets a valid reference or sees NULL and exits early.
Also change flush_work() to cancel_work_sync() to avoid running the partition scan work unnecessarily when the disk is already detached.
Weakness: CWE-416
Which versions are affected by CVE-2026-22995?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-22995?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-22995 being exploited?
There is no known exploitation of CVE-2026-22995 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-22995, DEBIAN-CVE-2026-22995, GHSA-hm7g-g733-g35g, UBUNTU-CVE-2026-22995.