# CVE-2025-40259: scsi: sg: Do not sleep in atomic context

> A local attacker can cause a system crash or hang by triggering a sleep in atomic context within the Linux kernel's SCSI generic driver.

- **Severity:** Not scored
- **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:** 4 Dec 2025
- **Updated:** 16 Jun 2026
- **Also known as:** AZL-71386, BELL-CVE-2025-40259, DEBIAN-CVE-2025-40259, GHSA-4cjv-m44p-782f, ROOT-OS-DEBIAN-11-CVE-2025-40259, ROOT-OS-DEBIAN-12-CVE-2025-40259, ROOT-OS-DEBIAN-13-CVE-2025-40259, ROOT-OS-UBUNTU-2204-CVE-2025-40259, ROOT-OS-UBUNTU-2404-CVE-2025-40259, UBUNTU-CVE-2025-40259

## What is CVE-2025-40259?

CVE-2025-40259 is a denial of service vulnerability in Linux, published on 4 Dec 2025. 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:

scsi: sg: Do not sleep in atomic context

sg_finish_rem_req() calls blk_rq_unmap_user(). The latter function may
sleep. Hence, call sg_finish_rem_req() with interrupts enabled instead
of disabled.

## Which versions are affected by CVE-2025-40259?


## How do I fix CVE-2025-40259?

Apply the vendor's patch.

## Is CVE-2025-40259 being exploited?

There is no known exploitation of CVE-2025-40259 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40259 and fix it if it is affected.

What it is: CVE-2025-40259 is a denial of service vulnerability in Linux, published on 4 Dec 2025. 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-2025-40259 in the wild and no public exploit code.

Affected product: Linux. 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-2025-40259/ (Markdown: https://insights.sbomify.com/CVE-2025-40259/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40259
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40259
- OSV: https://osv.dev/vulnerability/CVE-2025-40259

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40259/
Summaries are generated and may contain mistakes; the official description above is the record.