CVE-2026-40367CriticalRevised 20 May
Microsoft Word Remote Code Execution Vulnerability
Assessment
Access of resource using incompatible type ('type confusion') in Microsoft Office Word allows an unauthorized attacker to execute code locally.
- Severity
- Critical
- CVSS base score
- 8.4CVSS:3.1/
AV:L/ AC:L/ PR:N/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Remote Code Execution
- EPSS, next 30 days
- 0.4%Higher than 36.3% of scored CVEs · FIRST model run 29 Sep 2026 · about EPSS
- Public exploit code
- No Nuclei template lists it
- Exploitability
- Exploitation Unlikely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Microsoft Office Word
- Weakness
- CWE-822: Untrusted Pointer Dereference
- Issued by
- Microsoft
- Published
- 12 May 2026 · May 2026
- Last revised
- 20 May 2026The security impact for this vulnerability has been revised from Critical to Important. In addition, the CVSS vector and FAQs were modified. This change does not affect the available security updates. Customers should continue to install the recommended updates to remain protected from this vulnera…
Updates that fix it
6 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5002858 | Security Update | — | Microsoft Word 2016 (32-bit edition), Microsoft Word 2016 (64-bit edition) | All CVEs in KB5002858 |
| KB5002863 | Security Update | — | Microsoft SharePoint Server Subscription Edition | All CVEs in KB5002863 |
| KB5002868 | Security Update | — | Microsoft SharePoint Enterprise Server 2016 | All CVEs in KB5002868 |
| KB5002869 | Security Update | — | Microsoft SharePoint Enterprise Server 2016 | All CVEs in KB5002869 |
| KB5002870 | Security Update | — | Microsoft SharePoint Server 2019 | All CVEs in KB5002870 |
| KB5002872 | Security Update | — | Microsoft SharePoint Server 2019 | All CVEs in KB5002872 |
Affected products
Microsoft Office15 affected products
- Microsoft 365 Apps for Enterprise for 32-bit Systems
- Microsoft 365 Apps for Enterprise for 64-bit Systems
- Microsoft Office 2019 for 32-bit editions
- Microsoft Office 2019 for 64-bit editions
- Microsoft Office LTSC 2021 for 32-bit editions
- Microsoft Office LTSC 2021 for 64-bit editions
- Microsoft Office LTSC 2024 for 32-bit editions
- Microsoft Office LTSC 2024 for 64-bit editions
- Microsoft Office LTSC for Mac 2021
- Microsoft Office LTSC for Mac 2024
- Microsoft SharePoint Enterprise Server 2016
- Microsoft SharePoint Server 2019
- Microsoft SharePoint Server Subscription Edition
- Microsoft Word 2016 (32-bit edition)
- Microsoft Word 2016 (64-bit edition)