CVE-2026-42831
High
Description
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
SeverityHigh
CVSS7.8
Exploit probability—
Product
Microsoft Office
PublishedMay 12, 2026
First seenMay 12, 2026
Weakness typeCWE-122CWE-122
How to fix
Update
- microsoft 365_copilot16.0.19822.20190 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| microsoft office | 2024 | — |
| microsoft 365_copilot | v < 16.0.19822.20190 | 16.0.19822.20190 |
| microsoft office_long_term_servicing_channel | 2021 | — |
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