# CVE-2018-16882: Use after free in kernel:

> A guest user can trigger a use-after-free in the Linux kernel KVM hypervisor to crash the host or gain privileged access.

- **Severity:** Medium 6.1 (`CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:L/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Jan 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-16882, GHSA-4wh7-45g5-wcc8, UBUNTU-CVE-2018-16882

## What is CVE-2018-16882?

CVE-2018-16882 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 3 Jan 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A use-after-free issue was found in the way the Linux kernel's KVM hypervisor processed posted interrupts when nested(=1) virtualization is enabled. In nested_get_vmcs12_pages(), in case of an error while processing posted interrupt address, it unmaps the 'pi_desc_page' without resetting 'pi_desc' descriptor address, which is later used in pi_test_and_clear_on(). A guest user/process could use this flaw to crash the host kernel resulting in DoS or potentially gain privileged access to a system. Kernel versions before 4.14.91 and before 4.19.13 are vulnerable.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2018-16882?

It affects 2 products.


Products: Canonical Ubuntu Linux, Linux kernel.

## How do I fix CVE-2018-16882?

Apply the vendor's patch.

## Is CVE-2018-16882 being exploited?

There is no known exploitation of CVE-2018-16882 in the wild and no public exploit code.

## 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-2018-16882 and fix it if it is affected.

What it is: CVE-2018-16882 is a medium-severity use after free vulnerability in Canonical Ubuntu Linux, published on 3 Jan 2019. 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-2018-16882 in the wild and no public exploit code.

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-2018-16882/ (Markdown: https://insights.sbomify.com/CVE-2018-16882/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-16882
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-16882
- OSV: https://osv.dev/vulnerability/CVE-2018-16882

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-16882/
Summaries are generated and may contain mistakes; the official description above is the record.