# CVE-2026-45975: ublk: use READ_ONCE() to read struct ublksrv_ctrl_cmd

> A race condition in the Linux kernel ublk driver allows concurrent userspace writes to corrupt kernel state, potentially leading to undefined behavior.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 27 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-3q42-3w8p-xmr3, UBUNTU-CVE-2026-45975

## What is CVE-2026-45975?

CVE-2026-45975 is a medium-severity vulnerability in Linux kernel, published on 27 May 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: use READ_ONCE() to read struct ublksrv_ctrl_cmd

struct ublksrv_ctrl_cmd is part of the io_uring_sqe, which may lie in
userspace-mapped memory. It's racy to access its fields with normal
loads, as userspace may write to them concurrently. Use READ_ONCE() to
copy the ublksrv_ctrl_cmd from the io_uring_sqe to the stack. Use the
local copy in place of the one in the io_uring_sqe.

## Which versions are affected by CVE-2026-45975?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-45975?

Apply the vendor's patch.

## Is CVE-2026-45975 being exploited?

There is no known exploitation of CVE-2026-45975 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-2026-45975 and fix it if it is affected.

What it is: CVE-2026-45975 is a medium-severity vulnerability in Linux kernel, published on 27 May 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-2026-45975 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-2026-45975/ (Markdown: https://insights.sbomify.com/CVE-2026-45975/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45975
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45975
- OSV: https://osv.dev/vulnerability/CVE-2026-45975

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45975/
Summaries are generated and may contain mistakes; the official description above is the record.