Security readout for executives and security teams
Plain-English summary
This is a critical Microsoft Office app remote code execution vulnerability. The available record indicates an attacker could trigger code execution through a network-delivered attack path, but user interaction is required. Organizations should treat exposed Office users as high priority until Microsoft guidance and updates are confirmed.
Executive priority
Treat this as urgent patch management for Office users because impact is high and exploitation requires only user interaction, not attacker authentication.
Technical view
CVE-2021-43905 affects Microsoft Office app and is rated CVSS 9.6. The vector shows network attackability, low complexity, no privileges required, user interaction required, changed scope, and high confidentiality, integrity, and availability impact. The bundle lists Microsoft’s advisory as the remediation source.
Likely exposure
Exposure is most relevant where Microsoft Office app is installed and users can interact with untrusted Office-related content or links. The bundle does not provide exact affected builds, deployment channels, or platform details.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector includes proof-of-concept exploit maturity, but no offensive details are provided here.
Researcher notes
The public bundle is sparse: it confirms severity, affected product, CVSS vector, Microsoft advisory reference, and no KEV flag. It does not include root cause, file formats, affected build ranges, or detection indicators.
Mitigation direction
- Review the Microsoft MSRC advisory for affected builds and remediation status.
- Apply Microsoft-provided Office app updates where applicable.
- Prioritize users handling external documents, links, or attachments.
- Limit interaction with untrusted Office content until remediation is verified.
Validation and detection
- Inventory endpoints with Microsoft Office app installed.
- Compare installed versions against Microsoft’s advisory guidance.
- Verify update deployment through endpoint management or Microsoft update reporting.
- Check whether high-risk user groups received remediation first.
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-2021-43905 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
- Critical
- CVSS
- 9.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:P/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.
SSVC decision data
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:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C2.86microsoftVulnerability scoring details
Base CVSS 3.1 score
9.6CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43905CVE reference, microsoft · 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.