CVE-2026-21956 Denial of service in Oracle VM VirtualBox

High 8.2 Published 20 Jan 2026 Updated 26 Feb 2026

A local high-privileged attacker can exploit a resource exhaustion flaw in Oracle VM VirtualBox to compromise the hypervisor and impact other products.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-21956?

CVE-2026-21956 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 high privileged 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 takeover of Oracle VM VirtualBox. CVSS 3.1 Base Score 8.2 (Confidentiality, Integrity and Availability impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H).

Weakness: CWE-400

Which versions are affected by CVE-2026-21956?

It affects 1 product.

Products include Oracle Vm Virtualbox.

How do I fix CVE-2026-21956?

No fix has been published for CVE-2026-21956 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-21956 being exploited?

There is no known exploitation of CVE-2026-21956 in the wild and no public exploit code.

All Oracle Vm Virtualbox vulnerabilities

Sources

Also known as GHSA-r9hg-xj8m-mw5m, UBUNTU-CVE-2026-21956.