KB5002923: what it fixes and who gets it
KB5002923 is a security update from Microsoft's September 2026 release for Microsoft Office 2016 (32-bit edition), Microsoft Office 2016 (64-bit edition), Microsoft Word 2016 (32-bit edition) and other products.
Microsoft data read
Should you install it?
Yes. It closes holes Microsoft rates Critical, the most serious rating it uses. Windows Update installs it automatically on supported home PCs.
If the installation fails or the PC misbehaves afterwards, note the exact error code first: the fix depends on it. Our update troubleshooting guides are linked on this page.
Security fixes in KB5002923
| CVE | Type | CVSS | Severity |
|---|---|---|---|
| CVE-2026-78509Microsoft Office Outlook Remote Code Execution Vulnerability | Remote Code Execution | 9.8 | Critical |
| CVE-2026-78525Microsoft Office Outlook Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Critical |
| CVE-2026-78520Microsoft Office Outlook Information Disclosure Vulnerability | Remote Code Execution | 6.5 | Critical |
| CVE-2026-69556Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-69671Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-69686Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-69722Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-69759Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-69764Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-72972Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-72973Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-77901Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-78504Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-78511Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-78514Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-78517Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-78521Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-80080Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-80085Microsoft Office Word Remote Code Execution Vulnerability | Remote Code Execution | 8.8 | Important |
| CVE-2026-62804Microsoft Word Remote Code Execution Vulnerability | Remote Code Execution | 7.8 | Important |
| CVE-2026-69719Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-77911Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-78502Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-78503Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-78522Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-80079Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-80090Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 6.5 | Important |
| CVE-2026-78506Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 5.5 | Important |
| CVE-2026-83949Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 5.5 | Important |
| CVE-2026-83951Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 5.5 | Important |
| CVE-2026-72976Microsoft Office Word Information Disclosure Vulnerability | Information Disclosure | 5.0 | Important |
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