CVE-2026-21258
Medium
Description
Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.
SeverityMedium
CVSS5.5
Exploit probability—
Product
Microsoft Excel
PublishedFeb 10, 2026
First seenFeb 10, 2026
How to fix
Update
- microsoft office_online_server16.0.10417.20097 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| microsoft excel | 2016 | — |
| microsoft 365_apps | No range specified | — |
| microsoft office | 2019 | — |
| microsoft office_long_term_servicing_channel | 2021, 2024 | — |
| microsoft office_online_server | v < 16.0.10417.20097 | 16.0.10417.20097 |
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