# CVE-2019-6974: Use after free in n/a

> A race condition in the Linux kernel's KVM subsystem leads to a use-after-free, potentially allowing local attackers to execute code or escalate privileges.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Feb 2019
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-6974, GHSA-gvrg-rwmc-m69h, UBUNTU-CVE-2019-6974

## What is CVE-2019-6974?

CVE-2019-6974 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 15 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel before 4.20.8, kvm_ioctl_create_device in virt/kvm/kvm_main.c mishandles reference counting because of a race condition, leading to a use-after-free.

Weakness: CWE-416 (Use After Free), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2019-6974?

It affects 24 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, F5 Big-Ip Access Policy Manager, F5 Big-Ip Advanced Firewall Manager, F5 Big-Ip Analytics, F5 Big-Ip Application Acceleration Manager, F5 Big-Ip Application Security Manager, F5 Big-Ip Edge Gateway, F5 Big-Ip Fraud Protection Service, F5 Big-Ip Global Traffic Manager, F5 Big-Ip Link Controller, F5 Big-Ip Local Traffic Manager, F5 Big-Ip Policy Enforcement Manager, F5 Big-Ip Webaccelerator, Linux kernel, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Eus, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus and 4 more.

## How do I fix CVE-2019-6974?

Apply the vendor's patch.

## Is CVE-2019-6974 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-6974 exists.

Public exploit code:

- Linux - 'kvm_ioctl_create_device()' NULL Pointer Dereference (exploitdb)
- Linux - 'kvm_ioctl_create_device()' NULL Pointer Dereference (exploitdb)

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-6974 and fix it if it is affected.

What it is: CVE-2019-6974 is a high-severity use after free vulnerability in Canonical Ubuntu Linux, published on 15 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2019-6974 exists.

Affected product: Canonical Ubuntu 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-2019-6974/ (Markdown: https://insights.sbomify.com/CVE-2019-6974/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-6974
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-6974
- OSV: https://osv.dev/vulnerability/CVE-2019-6974

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-6974/
Summaries are generated and may contain mistakes; the official description above is the record.