# CVE-2026-124176

Heap overflow in Excel allows remote code execution via crafted spreadsheet.

- Page: https://www.vulneraibility.com/cve/CVE-2026-124176
- CVSS: 8.8
- Known exploited: not in CISA KEV as of our last sync
- EPSS: 0.61% (percentile 49.5)
- CISA SSVC: exploitation none, automatable no, technical impact total (assessed 2026-11-10)
- Weakness: CWE-122
- Published: 2026-11-10

## Affected versions

- Microsoft Microsoft 365 Apps for Enterprise: affected >= 16.0.1 and < https://aka.ms/OfficeSecurityReleases
- Microsoft Microsoft Office 365 for Mac: affected >= 1.0.0 and < 16.115.26110837
- Microsoft Microsoft Office LTSC 2021: affected >= 16.0.1 and < 16.0.14334.21048
- Microsoft Microsoft Office LTSC 2024: affected >= 16.0.0 and < 16.0.17932.21140
- Microsoft Microsoft Office LTSC for Mac 2021: affected >= 16.0.1 and < 16.115.26110837
- Microsoft Microsoft Office LTSC for Mac 2024: affected >= 16.0.0 and < 16.115.26110837
- Microsoft Office Online Server: affected >= 16.0.0.0 and < 16.0.10417.20236

A version outside these ranges is not a statement that it is unaffected.

## Impact

Remote code execution: attacker can run arbitrary code when a user opens a malicious Excel file, enabling malware, data theft, or lateral movement.

## Action

Immediate action required

## Recommendation

Apply Microsoft security update immediately; block untrusted Excel files.

## References

- [patch] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-124176

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Summary, impact and action are written by the vulneraibility.com AI analysis pipeline from the CVE record, NVD, CISA and FIRST data; verify against the references.