# CVE-2025-39870: dmaengine: idxd: Fix double free in idxd_setup_wqs()

> A double free vulnerability in the Linux kernel's idxd driver allows attackers to cause a denial of service or potentially execute arbitrary code.

- **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 Sep 2025
- **Updated:** 23 May 2026
- **Also known as:** BELL-CVE-2025-39870, DEBIAN-CVE-2025-39870, GHSA-c3f5-89cx-rxg5, UBUNTU-CVE-2025-39870

## What is CVE-2025-39870?

CVE-2025-39870 is a high-severity use after free vulnerability in Debian Debian Linux, published on 23 Sep 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:

dmaengine: idxd: Fix double free in idxd_setup_wqs()

The clean up in idxd_setup_wqs() has had a couple bugs because the error
handling is a bit subtle.  It's simpler to just re-write it in a cleaner
way.  The issues here are:

1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when
   "conf_dev" hasn't been initialized.
2) If kzalloc_node() fails then again "conf_dev" is invalid.  It's
   either uninitialized or it points to the "conf_dev" from the
   previous iteration so it leads to a double free.

It's better to free partial loop iterations within the loop and then
the unwinding at the end can handle whole loop iterations.  I also
renamed the labels to describe what the goto does and not where the goto
was located.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2025-39870?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39870?

Apply the vendor's patch.

## Is CVE-2025-39870 being exploited?

There is no known exploitation of CVE-2025-39870 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39870 and fix it if it is affected.

What it is: CVE-2025-39870 is a high-severity use after free vulnerability in Debian Debian Linux, published on 23 Sep 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-2025-39870 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-39870/ (Markdown: https://insights.sbomify.com/CVE-2025-39870/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39870
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39870
- OSV: https://osv.dev/vulnerability/CVE-2025-39870

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39870/
Summaries are generated and may contain mistakes; the official description above is the record.