Security readout for executives and security teams
Plain-English summary
CVE-2021-42292 is a Microsoft Excel security feature bypass affecting several supported Office and Excel lines. It matters because CISA lists it as known exploited, so this is not theoretical. Successful exploitation requires user interaction and could affect confidentiality, integrity, and availability according to the supplied CVSS data.
Executive priority
Treat as a high-priority endpoint remediation item because CISA confirms known exploitation and Office document handling is common across business users. Focus first on users likely to receive external spreadsheets, then complete fleet-wide Office update validation.
Technical view
The supplied CVSS 3.1 vector is 7.8 High: local attack vector, low complexity, no privileges required, user interaction required, unchanged scope, and high C/I/A impact. Affected products include Excel 2013 SP1, Excel 2016, Office 2013/2016/2019, Office LTSC 2021, Office for Mac variants, and Microsoft 365 Apps for Enterprise.
Likely exposure
Organizations are exposed if users run affected Microsoft Excel or Office builds listed in the advisory, including legacy 2013/2016 deployments, Office 2019, LTSC 2021, Mac editions, or Microsoft 365 Apps for Enterprise that have not received the relevant Microsoft update.
Exploitation context
Active exploitation is supported by the CISA Known Exploited Vulnerabilities listing. The provided sources do not describe the bypass mechanism, exploit chain, payload, indicators, or whether exploitation is widespread or targeted.
Researcher notes
Evidence is limited to the advisory metadata and KEV status. The source bundle does not provide technical root cause, exploit details, IOCs, or detection logic. Avoid assuming remote code execution or a specific delivery method beyond user interaction and affected Excel/Office exposure.
Mitigation direction
- Apply Microsoft security updates referenced by the MSRC advisory.
- Prioritize affected Office and Excel assets that open external spreadsheets.
- Verify Microsoft 365 Apps update channels are current.
- Retire or isolate unsupported legacy Office installations.
- Restrict untrusted spreadsheet handling until updates are confirmed.
Validation and detection
- Inventory installed Office and Excel products against the affected list.
- Compare installed builds with Microsoft’s MSRC guidance.
- Confirm patched endpoints no longer match affected versions.
- Review vulnerability management tools for CVE-2021-42292 findings.
- Check CISA KEV-driven remediation tracking for closure evidence.
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.
CVE-2021-42292 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
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/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.
CISA KEV status
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:P/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:P/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42292CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42292CVE reference · government-resource
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.