Security readout for executives and security teams
Plain-English summary
CVE-2021-35540 is a denial-of-service flaw in Oracle VM VirtualBox. A logged-in, low-privileged local user on a system running affected VirtualBox could make VirtualBox hang or crash repeatedly. The sources do not indicate data theft, privilege escalation, or remote exploitation.
Executive priority
Handle as a moderate availability risk. Patch during normal maintenance unless VirtualBox supports critical operations or runs on shared systems with broad local user access, where priority should increase.
Technical view
Oracle describes this as a Core component vulnerability in VM VirtualBox prior to 6.1.28. CVSS 3.1 is 5.5: local attack, low complexity, low privileges, no user interaction, unchanged scope, no confidentiality or integrity impact, and high availability impact.
Likely exposure
Exposure is most likely on endpoints, lab systems, build machines, or shared infrastructure where Oracle VM VirtualBox is installed below 6.1.28 and low-privileged users can log on locally.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires local logon access to infrastructure where VirtualBox executes, limiting reach but still affecting availability on shared or operational hosts.
Researcher notes
Evidence is limited to Oracle and Gentoo advisory material. No CWE is listed in the bundle. The known impact is complete denial of service for VirtualBox, not host compromise or data exposure.
Mitigation direction
- Upgrade Oracle VM VirtualBox to 6.1.28 or later.
- Apply relevant OS or distribution security updates, including Gentoo guidance if applicable.
- Restrict local logon access on systems running VirtualBox.
- Prioritize shared hosts where untrusted or many users can log in.
Validation and detection
- Inventory systems with Oracle VM VirtualBox installed.
- Confirm installed VirtualBox versions are not prior to 6.1.28.
- Review whether low-privileged users can log on to those hosts.
- Check logs or support tickets for repeated VirtualBox hangs or crashes.
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-2021-35540 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
- Medium
- CVSS
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.oracle.com/security-alerts/cpuoct2021.htmlCVE 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.