CVE-2026-97778: Microsoft Office Excel Remote Code Execution Vulnerability
Integer overflow or wraparound in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
- Published by source
- 2026-10-13
- First seen by Reality Radar
- 2026-10-22
- Last verified
- 2026-10-22
Affected
- Manufacturer
- Microsoft
- Products
- Office Online Server Microsoft Office 365 for Mac Microsoft Office LTSC for Mac 2021 Microsoft Office LTSC for Mac 2024 Microsoft Office LTSC 2021 for Microsoft Office LTSC 2024 for Microsoft 365 Apps for Enterprise for 64-bit Systems Microsoft 365 Apps for Enterprise
- CPE
- cpe:2.3:a:microsoft:office_2021:*:*:*:*:ltsc:*:*:*
cpe:2.3:a:microsoft:office_365:*:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*
cpe:2.3:a:microsoft:office_macos_2024:*:*:*:*:*:long_term_servicing_channel:*:*
cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*
Whether your exact unit is affected depends on the model, serial number and region in the official notice.
What the official notice says
Risk: Critical — Remote Code Execution
Remedy / actions:
- Install the security update: https://support.microsoft.com/help/5002928
Is this affecting you?
Add what you own or use and Reality Radar will tell you when official changes match it — with evidence and next steps.
Sources
- Microsoft Security Update Guide (MSRC) Tier A · official published 2026-10-13
Evidence ledger
Every piece of evidence we store is appended to a public hash chain, so later edits are detectable. Anyone can re-verify it.
| Entry | Kind | Observed | Evidence hash | Entry hash |
|---|---|---|---|---|
| #189 | new | 2026-10-22 | 6652d87fe65a…c326f4 | ca90cfeee799…7d88fe |
Chain head: #1076 8ad5adc30b9b…88ce20