Security readout for executives and security teams
Plain-English summary
CVE-2021-31940 is a high-severity Microsoft Office graphics vulnerability. A successful attack could let an attacker run code after a user opens malicious Office content. The main business risk is workstation compromise, data access, and possible follow-on activity from affected Office installations.
Executive priority
Treat as a standard high-priority endpoint patching issue. Prioritize users who handle external documents, finance, legal, HR, and executives. Urgency is meaningful, but the provided evidence does not support claiming known active exploitation.
Technical view
The CVSS 3.1 score is 7.8 with local attack vector, low complexity, no privileges required, and required user interaction. Scope is unchanged, with high confidentiality, integrity, and availability impact. Microsoft lists affected Office 2013 SP1, Office 2016, Office 2019, Office 2019 for Mac, and Microsoft 365 Apps for Enterprise.
Likely exposure
Exposure is most likely on endpoints running the listed Microsoft Office versions, especially where users receive external documents or attachments. The bundle does not identify server-side exposure or non-Microsoft products.
Exploitation context
The source bundle does not show CISA KEV inclusion or active exploitation. The CVSS vector indicates exploitation requires local interaction, likely a user opening crafted content, and Microsoft marks exploit code maturity as unproven in the provided vector.
Researcher notes
Evidence is limited to public CVE and Microsoft advisory metadata. No CWE, exploit details, or named exploit campaigns are provided. Avoid assumptions beyond affected Office products, user-interaction requirement, high impact, and official remediation availability indicated by the CVSS remediation level.
Mitigation direction
- Apply the Microsoft updates referenced in the MSRC advisory.
- Confirm affected Office builds are no longer present in managed endpoint inventory.
- Limit exposure to untrusted Office documents through email and web controls.
- Review Microsoft guidance for any product-specific update prerequisites.
Validation and detection
- Inventory Office 2013 SP1, 2016, 2019, 2019 for Mac, and Microsoft 365 Apps endpoints.
- Compare installed Office build levels against Microsoft’s CVE-2021-31940 advisory.
- Confirm endpoint management reports successful Office update installation.
- Review security telemetry for suspicious Office document handling around exposed endpoints.
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-2021-31940 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-2021-31940CVE 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.