Security readout for executives and security teams
Plain-English summary
This Microsoft Office flaw can allow remote code execution, potentially compromising data and system integrity. The listed affected releases are Office 2010 SP2, Office 2013 SP1, and Office 2016. CISA KEV inclusion confirms exploitation has occurred, making unpatched installations a priority despite the vulnerability’s high attack complexity and interaction requirements.
Executive priority
Treat as a high-priority remediation because exploitation is documented and successful compromise could have severe business impact. Establish the affected asset count, apply Microsoft’s update, and verify closure promptly. Escalate unsupported or unpatchable installations for replacement, isolation, or vendor-directed mitigation.
Technical view
CVE-2021-27059 is a Microsoft Office remote-code-execution vulnerability rated CVSS 3.1 7.6 (high). The supplied vector indicates network reachability, high attack complexity, high required privileges, required user interaction, changed scope, and high confidentiality, integrity, and availability impact. The bundle does not describe the vulnerable component, exploitation mechanism, or applicable update identifiers.
Likely exposure
Exposure is most likely where the listed Office 2010 SP2, Office 2013 SP1, or Office 2016 releases remain installed without Microsoft’s applicable security update. The bundle does not establish whether other Office editions, builds, platforms, or configurations are affected.
Exploitation context
CISA KEV status supports known exploitation in the wild. However, the supplied evidence does not identify campaigns, threat actors, exploitation volume, or technical indicators. The CVSS vector indicates exploitation is constrained by high complexity, high privileges, and required user interaction; these constraints do not remove the demonstrated risk.
Researcher notes
The source bundle provides severity, CVSS vector, affected Office releases, vendor references, and KEV status, but no root cause, vulnerable component, proof-of-concept status, indicators, patch identifiers, or attack telemetry. Avoid inferring document formats, delivery methods, or observed threat actors without additional authoritative evidence.
Mitigation direction
- Identify installations of the three listed Microsoft Office releases.
- Consult the Microsoft advisory for applicable security updates and supported remediation.
- Apply the applicable Microsoft updates using established change-control procedures.
- Prioritize exposed or high-value endpoints where affected Office versions remain installed.
- Follow current Microsoft guidance if an affected release cannot be updated promptly.
Validation and detection
- Confirm Office product, version, build, and update status on managed endpoints.
- Compare installed updates with the remediation listed in Microsoft’s CVE advisory.
- Verify deployment success through endpoint-management and vulnerability-scanning records.
- Re-scan affected assets and investigate any remaining CVE-2021-27059 detections.
- Review security alerts and incident records for activity associated with this CVE.
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-2021-27059 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
- 7.6 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/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.
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:N/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C16microsoftVulnerability scoring details
Base CVSS 3.1 score
7.6HighVector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:H/E:U/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-2021-27059 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2021-11-03T00:00:00.000Z: CVE-2021-27059 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Office Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27059CVE reference, CVE · x_refsource_MISC, x_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27059CVE 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.