# CVE-2018-12904: Privilege escalation in n/a

> Local attackers can escalate privileges or cause denial of service in nested virtualization environments due to missing CPL checks in the Linux kernel KVM module.

- **Severity:** Medium 4.9 (`CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-12904, GHSA-vx6h-cqmq-qj84, UBUNTU-CVE-2018-12904

## What is CVE-2018-12904?

CVE-2018-12904 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 27 Jun 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In arch/x86/kvm/vmx.c in the Linux kernel before 4.17.2, when nested virtualization is used, local attackers could cause L1 KVM guests to VMEXIT, potentially allowing privilege escalations and denial of service attacks due to lack of checking of CPL.

## Which versions are affected by CVE-2018-12904?

It affects 2 products.


Products: Canonical Ubuntu Linux, Linux kernel.

## How do I fix CVE-2018-12904?

Apply the vendor's patch.

## Is CVE-2018-12904 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-12904 exists.

Public exploit code:

- KVM (Nested Virtualization) - L1 Guest Privilege Escalation (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-2018-12904 and fix it if it is affected.

What it is: CVE-2018-12904 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 27 Jun 2018. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-12904 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-2018-12904/ (Markdown: https://insights.sbomify.com/CVE-2018-12904/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-12904
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-12904
- OSV: https://osv.dev/vulnerability/CVE-2018-12904

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-12904/
Summaries are generated and may contain mistakes; the official description above is the record.