CVE-2026-88156: Microsoft Office Outlook Remote Code Execution Vulnerability
Stack-based buffer overflow in Microsoft Office Outlook 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
- Microsoft Office 365 for Mac Microsoft 365 Apps for Enterprise Microsoft 365 Apps for Enterprise for 64-bit Systems Microsoft Office LTSC for Mac 2021 Microsoft Office LTSC 2021 for Microsoft Office LTSC 2024 for Microsoft Office LTSC for Mac 2024
- CPE
- cpe:2.3:a:microsoft:office_365:*:*:*:*:*:macos:*:*
cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*
cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*
cpe:2.3:a:microsoft:office_2024:*:*:*:*: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 latest Microsoft security update
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 |
|---|---|---|---|---|
| #157 | new | 2026-10-22 | 0881768a63e1…deae14 | 8997f5dc7b3c…8e490a |
Chain head: #1076 8ad5adc30b9b…88ce20