Security readout for executives and security teams
Plain-English summary
CVE-2021-31967 is a high-severity Microsoft VP9 Video Extensions remote code execution issue. Affected systems could be compromised if a user interacts with malicious VP9-related content or a triggering local vector. The provided sources do not show active exploitation.
Executive priority
Treat this as a high-priority endpoint patching issue, not an emergency exploitation incident based on current evidence. Focus on identifying affected Windows systems and applying Microsoft guidance promptly.
Technical view
The source bundle identifies Microsoft VP9 Video Extensions version 1.0.0.0 as affected. CVSS 3.1 score is 7.8 with AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, meaning low complexity, no privileges required, user interaction required, and high impact after exploitation.
Likely exposure
Exposure is most likely on Windows endpoints with the affected Microsoft VP9 Video Extensions package installed. Prioritize user workstations that open externally supplied media content or receive files from email, web, chat, or shared drives.
Exploitation context
The bundle marks KEV as false and CVSS exploit maturity as unproven. There is no cited evidence of active exploitation. User interaction is required, so phishing, malicious media delivery, or social engineering would be plausible risk contexts, but exact exploit mechanics are not provided.
Researcher notes
Evidence is limited to CVE metadata and the Microsoft advisory reference. The CVSS vector indicates local attack vector and required user interaction despite the RCE title. Do not assume internet-exposed service risk from the provided data.
Mitigation direction
- Check the Microsoft MSRC advisory for official remediation guidance.
- Update Microsoft VP9 Video Extensions through supported Microsoft update channels.
- Inventory endpoints for affected VP9 Video Extensions installations.
- Restrict untrusted media handling until remediation is confirmed.
- Prioritize patching endpoints used for email, browsing, and file intake.
Validation and detection
- Confirm installed VP9 Video Extensions version on Windows endpoints.
- Verify remediation status against Microsoft MSRC guidance.
- Review endpoint software inventory for version 1.0.0.0.
- Check whether users can open untrusted VP9 media files.
- Monitor Microsoft advisory updates for revised affected-version data.
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.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-31967 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
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:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31967CVE reference · x_refsource_MISC
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.