Security readout for executives and security teams
Plain-English summary
This Excel flaw can bypass a security protection and may lead to severe loss of confidentiality, integrity, and availability after user interaction. CISA lists it as known exploited, making unsupported or unpatched affected Office installations a priority even though the supplied sources do not describe the attack mechanism.
Executive priority
Treat remediation as urgent for affected, unpatched installations. Known exploitation and potentially high business impact justify accelerated inventory and patch verification. Escalate systems that cannot be updated, but do not assume compromise without supporting telemetry.
Technical view
CVE-2021-42292 is a Microsoft Excel security-feature bypass rated CVSS 7.8. The supplied vector indicates local access, low complexity, no privileges, required user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. Technical root cause and exploitation indicators are not provided.
Likely exposure
Exposure includes the listed Microsoft 365 Apps, Excel 2013 SP1, Excel 2016, Office 2013 SP1, Office 2016, Office 2019, and Office LTSC 2021 variants, including specified Mac editions. Actual exposure depends on installed builds and security-update status.
Exploitation context
CISA KEV inclusion supports that this vulnerability has been exploited in the wild. The supplied evidence does not identify threat actors, campaign scope, exploitation frequency, file characteristics, indicators of compromise, or whether exploitation remains widespread.
Researcher notes
The source bundle confirms classification, affected product families, CVSS characteristics, Microsoft patch guidance, and KEV status. It does not provide a weakness identifier, root cause, proof-of-concept details, exploit chain, detection signatures, fixed build numbers, or named mitigations. Consult the current Microsoft advisory for product-specific remediation data.
Mitigation direction
- Use Microsoft’s advisory to identify and install the applicable security update for each affected product.
- Prioritize affected installations because CISA identifies the vulnerability as known exploited.
- Restrict interaction with untrusted Excel content until update status is verified.
- Check Microsoft guidance for interim mitigations if immediate updating is impossible.
Validation and detection
- Inventory installed Microsoft Excel, Office, Microsoft 365 Apps, and LTSC versions across Windows and macOS.
- Compare installed builds and updates with the product-specific information in Microsoft’s advisory.
- Confirm update deployment succeeded on every identified affected endpoint.
- Review security telemetry for suspicious Office activity; the supplied sources provide no specific indicators.
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
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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C1.85.9microsoftVulnerability 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
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.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2021-42292 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2021-11-17T00:00:00.000Z: CVE-2021-42292 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Excel Security Feature Bypass VulnerabilityCVE reference, microsoft · vendor-advisory, patch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42292CVE reference, CVE · x_refsource_MISC, x_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42292CVE reference, CISA-ADP · 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.