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PatchSiren cyber security CVE debrief

CVE-2021-42292 Microsoft CVE debrief

CVE-2021-42292 is a Microsoft Excel security feature bypass affecting Microsoft Office. It was added to CISA’s Known Exploited Vulnerabilities catalog on 2021-11-17, which means defenders should treat it as actively exploited and prioritize remediation. CISA’s listed required action is to apply updates per vendor instructions.

Vendor
Microsoft
Product
Office
CVSS
HIGH 7.8
CISA KEV
Listed
Original CVE published
2021-11-17
Original CVE updated
2021-11-17
Advisory published
2021-11-17
Advisory updated
2021-11-17

Who should care

Microsoft Office and Excel administrators, endpoint management teams, security operations staff, and organizations with large Office deployments should prioritize this issue, especially where patch compliance is centrally managed.

Technical summary

The supplied corpus identifies the issue as a security feature bypass in Microsoft Excel within Microsoft Office. No CVSS score is provided in the supplied records. Because CISA included it in the Known Exploited Vulnerabilities catalog, it should be handled as a confirmed exploitation-risk item and remediated through vendor updates.

Defensive priority

High. CISA KEV inclusion and the stated remediation deadline indicate urgent patching and verification are warranted.

Recommended defensive actions

  • Apply Microsoft updates per vendor instructions.
  • Inventory Microsoft Office and Excel installations to confirm exposure.
  • Verify patch compliance across managed endpoints and servers that include Office components.
  • Prioritize remediation using the CISA KEV due date of 2021-12-01 as the historical urgency marker.
  • Track completion in vulnerability management and exception workflows until all affected systems are updated.

Evidence notes

The supplied source corpus names the issue as “Microsoft Office Microsoft Excel Security Feature Bypass” and “Microsoft Excel Security Feature Bypass,” with vendor/product listed as Microsoft/Office. CISA KEV metadata states “Apply updates per vendor instructions,” dateAdded 2021-11-17, dueDate 2021-12-01, and knownRansomwareCampaignUse Unknown. No CVSS score or additional technical exploit details are provided in the supplied material.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-42292 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-42292

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-42292 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-42292

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.