Security readout for executives and security teams
Plain-English summary
CVE-2021-2309 is a high-severity Oracle VM VirtualBox Core vulnerability affecting versions before 6.1.20. Exploitation requires local access with high privileges and is described as difficult, but successful exploitation can take over VirtualBox and may affect additional products running through it.
Executive priority
Treat this as a high-priority patching and exposure-reduction item for systems that run VirtualBox, especially shared infrastructure. It is less urgent than remotely exploitable internet-facing flaws, but compromise impact is high if an attacker already has privileged local access.
Technical view
Oracle describes this as a local, high-complexity, high-privilege VirtualBox Core flaw with changed scope and high confidentiality, integrity, and availability impact. The source bundle does not identify a CWE or detailed root cause. The affected supported version range is prior to 6.1.20.
Likely exposure
Exposure is most likely on developer workstations, build hosts, labs, or servers running Oracle VM VirtualBox before 6.1.20. The attacker already needs privileged logon to the infrastructure where VirtualBox executes, reducing broad internet exposure but increasing concern on shared or multi-user systems.
Exploitation context
The sources do not show known active exploitation, and CISA KEV status is false. Oracle rates exploitation as difficult and requiring local high privileges. The business risk is post-access escalation or compromise of virtualization infrastructure, not unauthenticated remote compromise.
Researcher notes
The public bundle confirms impact, CVSS vector, affected version boundary, and advisory references, but not root cause details or exploit mechanics. Avoid assuming exploit availability. Focus validation on version inventory, privilege boundaries, host access, and whether VirtualBox supports sensitive workflows.
Mitigation direction
- Upgrade Oracle VM VirtualBox to 6.1.20 or later following Oracle guidance.
- Apply relevant OS distributor updates, including Gentoo GLSA guidance where applicable.
- Restrict privileged logon access to systems running VirtualBox.
- Review shared virtualization hosts for unnecessary users and stale admin accounts.
Validation and detection
- Inventory hosts running Oracle VM VirtualBox and record installed versions.
- Confirm no VirtualBox installation remains below 6.1.20.
- Check whether VirtualBox runs on shared, build, lab, or privileged-user systems.
- Review access logs for unexpected privileged logons on VirtualBox hosts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-2309 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H0.86Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.oracle.com/security-alerts/cpuapr2021.htmlCVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-461/CVE reference · x_refsource_MISC
- GLSA-202208-36CVE reference · vendor-advisory, x_refsource_GENTOO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.