Security readout for executives and security teams
Plain-English summary
CVE-2021-31175 is a high-severity Microsoft Office remote code execution issue. It affects several Office, Excel, Microsoft 365 Apps, Office Online Server, and Office Web Apps Server releases. A successful attack requires user interaction, so business risk is highest where affected Office products process untrusted files or content.
Executive priority
Prioritize remediation in normal high-severity patch cycles, with faster action for users and services handling external documents. There is no provided evidence of active exploitation, but impact is severe if exploited.
Technical view
The supplied CVSS 3.1 vector is 7.8 high: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. No privileges are required, attack complexity is low, user interaction is required, and successful exploitation can impact confidentiality, integrity, and availability. The source bundle indicates an official fix is available.
Likely exposure
Exposure is likely on endpoints or servers running the listed Microsoft Office, Excel, Microsoft 365 Apps for Enterprise, Office Online Server, or Office Web Apps Server versions that have not applied Microsoft guidance.
Exploitation context
The bundle does not show CISA KEV listing or cited active exploitation. Treat this as a user-interaction-driven Office RCE risk, not confirmed active exploitation based on the provided evidence.
Researcher notes
The supplied data lacks CWE detail and does not include exploit mechanics. Validate against Microsoft’s advisory and ZDI-21-580, focus on version exposure and patch state, and avoid assuming exploitation beyond user interaction and CVSS indicators.
Mitigation direction
- Review the MSRC advisory for affected product-specific updates.
- Apply Microsoft security updates for all listed affected Office products.
- Prioritize systems that process external or untrusted Office content.
- Retire or upgrade affected legacy Office and Office server deployments.
- Use existing email and endpoint controls to reduce untrusted Office content exposure.
Validation and detection
- Inventory installed Office, Excel, Microsoft 365 Apps, and Office server versions.
- Compare installed versions against the affected products in the source bundle.
- Confirm the relevant Microsoft security updates are installed.
- Check vulnerability scanner results against CVE-2021-31175 after patching.
- Verify Office server roles are included in patch compliance reporting.
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-2021-31175 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-2021-31175CVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-580/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.