# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 23 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-22995, DEBIAN-CVE-2026-22995, GHSA-hm7g-g733-g35g, UBUNTU-CVE-2026-22995

## 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 (Use After Free)

## Which versions are affected by CVE-2026-22995?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-22995?

Apply the vendor's patch.

## 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22995 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-22995 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-22995/ (Markdown: https://insights.sbomify.com/CVE-2026-22995/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22995
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22995
- OSV: https://osv.dev/vulnerability/CVE-2026-22995

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22995/
Summaries are generated and may contain mistakes; the official description above is the record.