Security readout for executives and security teams
Plain-English summary
CVE-2025-21362 is a high-severity Microsoft Excel remote code execution vulnerability. The provided sources identify affected Microsoft 365 Apps, Excel 2016, Office 2019, Office LTSC, Mac LTSC, and Office Online Server versions. Microsoft has published a patch advisory. No provided source says it is actively exploited.
Executive priority
Patch as a high-priority vulnerability, especially where Office is widely deployed or handles sensitive documents. The business urgency is elevated by code-execution impact, but the provided evidence does not show active exploitation.
Technical view
The bundle describes a Microsoft Excel RCE with CVSS 3.1 score 8.4 and CWE-416 use-after-free. The vector is AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, indicating low complexity, no privileges, and high confidentiality, integrity, and availability impact. The provided evidence does not include exploit mechanics.
Likely exposure
Organizations running listed Microsoft Office, Excel, Microsoft 365 Apps for Enterprise, Mac LTSC, or Office Online Server versions without the Microsoft security update may be exposed. Actual exposure depends on installed products, update channel, and patch status.
Exploitation context
The source bundle marks KEV as false and CVSS exploit maturity as unproven. Based on the provided sources, there is no confirmed active exploitation. Treat it as serious because successful exploitation could allow code execution with high impact.
Researcher notes
Evidence is limited to Microsoft and CVE metadata. The key technical clue is CWE-416 use-after-free, but the bundle provides no root cause detail, exploit primitive, affected file format, or proof-of-concept status. Avoid assuming attack delivery beyond the published CVSS vector.
Mitigation direction
- Apply Microsoft’s security update for CVE-2025-21362.
- Prioritize Office Online Server and high-value user workstations.
- Confirm Microsoft 365 Apps and Office LTSC update channels are current.
- Review Microsoft’s advisory for product-specific remediation guidance.
- Monitor MSRC for revisions to affected products or guidance.
Validation and detection
- Inventory systems running the affected Microsoft Office and Excel products.
- Compare installed versions and channels against Microsoft’s CVE advisory.
- Confirm endpoint management reports show the relevant security update installed.
- Check vulnerability scanner results for CVE-2025-21362 coverage.
- Verify Office Online Server patch status separately from desktop Office.
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.
CWE-416: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution 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-2025-21362 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
- 8.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/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:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RC:C2.55.9microsoftVulnerability scoring details
Base CVSS 3.1 score
8.4HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/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
- Microsoft Excel Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.