Security readout for executives and security teams
Plain-English summary
CVE-2021-31179 is a high-severity Microsoft Office remote code execution flaw. It affects several Office, Excel, Microsoft 365 Apps for Enterprise, Office Online Server, and Office Web Apps Server versions. The scoring shows user interaction is required, so business risk is primarily from users or services processing malicious Office content.
Executive priority
Prioritize remediation in the normal high-severity patch cycle, with faster handling for users or servers that process external Office documents. No active exploitation is cited in the supplied sources, but impact is high if exploited.
Technical view
The vulnerability is rated CVSS 3.1 7.8 with AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Sources identify it as Microsoft Office remote code execution. The bundle does not describe the vulnerable component, trigger condition, or exploit mechanics. Remediation status is listed as official fix available through Microsoft guidance.
Likely exposure
Organizations using affected Microsoft Office 2013 SP1, Office 2016, Office 2019, Excel 2013/2016, Microsoft 365 Apps for Enterprise, Office Online Server, or Office Web Apps Server 2013 may be exposed if not updated.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. CVSS indicates no privileges are required, attack complexity is low, and user interaction is required. Treat this as a document-handling risk unless Microsoft guidance provides more specific conditions.
Researcher notes
Evidence is limited to CVE metadata and Microsoft advisory references. The bundle confirms affected products, CVSS, user interaction, and official remediation availability, but does not provide component-level root cause, exploit telemetry, or workaround detail.
Mitigation direction
- Apply Microsoft updates referenced by the MSRC advisory.
- Prioritize systems running affected Office, Excel, Office Online Server, and Web Apps Server versions.
- Check Microsoft guidance for product-specific update channels and prerequisites.
- Reduce exposure to untrusted Office files until patch status is confirmed.
Validation and detection
- Inventory installed Office, Excel, Microsoft 365 Apps, and server-side Office products.
- Compare installed versions and patch levels against the MSRC advisory.
- Confirm Office Online Server and Web Apps Server deployments are included in patch checks.
- Review endpoint management reports for failed or pending Microsoft Office updates.
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-2021-31179 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-2021-31179CVE 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.