Security readout for executives and security teams
Plain-English summary
CVE-2021-31176 is a high-severity Microsoft Office remote code execution issue. Business risk is mainly endpoint compromise through Office use, with user interaction required. The supplied sources do not show CISA KEV listing or active exploitation evidence.
Executive priority
Treat as a patch-priority endpoint risk, especially in environments with frequent external document handling. Urgency is high but not emergency-level based on the supplied evidence because active exploitation is not shown.
Technical view
The CVSS 3.1 vector is 7.8: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Affected products listed include Office 2013 SP1, Office 2016, Office 2019, and Microsoft 365 Apps for Enterprise. The bundle does not provide component-level root cause details.
Likely exposure
Exposure is likely where affected Microsoft Office versions remain installed on managed or unmanaged endpoints. This is not described as internet-facing service exposure; the CVSS vector indicates local attack conditions and required user interaction.
Exploitation context
The bundle does not cite active exploitation, and KEV is false. Exploitation would require a user interaction path involving Microsoft Office, but the supplied sources do not provide exploit mechanics or a confirmed public attack campaign.
Researcher notes
The public bundle supports severity, affected product families, CVSS semantics, and official references, but not root cause, file format, exploit maturity beyond CVSS E:U, or detailed mitigation beyond Microsoft guidance.
Mitigation direction
- Review Microsoft’s CVE-2021-31176 advisory for applicable Office updates.
- Patch affected Office and Microsoft 365 Apps installations through normal update channels.
- Prioritize endpoints handling external or untrusted Office documents.
- Check vendor guidance before applying compensating controls not listed in the advisory.
Validation and detection
- Inventory installed Microsoft Office versions against the affected product list.
- Confirm Office security updates corresponding to CVE-2021-31176 are installed.
- Review vulnerability scanner findings for stale Office 2013, 2016, 2019, and 365 Apps builds.
- Document any unsupported or unmanaged Office installations for remediation tracking.
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-2021-31176 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-2021-31176CVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-575/CVE 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.