# CVE-2026-21986: Denial of service in Oracle VM VirtualBox

> An unauthenticated attacker with local access can cause a complete denial of service in Oracle VM VirtualBox on Windows VMs.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jan 2026
- **Updated:** 23 Jan 2026
- **Also known as:** GHSA-pmq9-qqvr-3fjc, UBUNTU-CVE-2026-21986

## What is CVE-2026-21986?

CVE-2026-21986 is a high-severity denial of service vulnerability in Oracle Vm Virtualbox, published on 20 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Vulnerability in the Oracle VM VirtualBox product of Oracle Virtualization (component: Core).  Supported versions that are affected are 7.1.14 and  7.2.4. Easily exploitable vulnerability allows unauthenticated attacker with logon to the infrastructure where Oracle VM VirtualBox executes to compromise Oracle VM VirtualBox.  While the vulnerability is in Oracle VM VirtualBox, attacks may significantly impact additional products (scope change).  Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Oracle VM VirtualBox. Note: This vulnerability applies to Windows VMs only. CVSS 3.1 Base Score 7.1 (Availability impacts).  CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H).

## Which versions are affected by CVE-2026-21986?

It affects 1 product.


Products: Oracle Vm Virtualbox.

## How do I fix CVE-2026-21986?

No fix has been published for CVE-2026-21986 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21986 being exploited?

There is no known exploitation of CVE-2026-21986 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-21986: VirtualBox Shared Folders kernel memory exhaustion DoS (github_poc): https://github.com/MohaBars/CVE-2026-21986-VirtualBox-DoS

## Other vulnerabilities in Oracle Vm Virtualbox

- [CVE-2016-5605](https://insights.sbomify.com/CVE-2016-5605/): Unspecified vulnerability in the Oracle VM VirtualBox component before 5.1.4 in Oracle Virtualization allows remote attackers to affect conf (critical 9.1)
- [CVE-2018-3294](https://insights.sbomify.com/CVE-2018-3294/): Privilege escalation in VM VirtualBox (critical 9.0)
- [CVE-2024-21112](https://insights.sbomify.com/CVE-2024-21112/): Privilege escalation in VM VirtualBox (high 8.8)
- [CVE-2024-21113](https://insights.sbomify.com/CVE-2024-21113/): Privilege escalation in VM VirtualBox (high 8.8)
- [CVE-2024-21114](https://insights.sbomify.com/CVE-2024-21114/): Privilege escalation in VM VirtualBox (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21986 and fix it if it is affected.

What it is: CVE-2026-21986 is a high-severity denial of service vulnerability in Oracle Vm Virtualbox, published on 20 Jan 2026. 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-2026-21986 in the wild and no public exploit code.

Affected product: Oracle Vm Virtualbox. 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-2026-21986/ (Markdown: https://insights.sbomify.com/CVE-2026-21986/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21986
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21986
- OSV: https://osv.dev/vulnerability/CVE-2026-21986

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21986/
Summaries are generated and may contain mistakes; the official description above is the record.