# KB5002835: February 2026 security update

KB5002835, released February 10, 2026, fixes 3 CVEs in Office Online Server. None of them is reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/fix/microsoft/kb5002835
- Platform: Microsoft
- Released: Feb 10, 2026
- Priority: High (Closes CVE-2026-21259, high severity)
- CVEs: 3, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5002835

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Office Online Server](https://patchblox.com/security/data/product/microsoft/office-online-server.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-21259](https://patchblox.com/security/data/cve/CVE-2026-21259.md) | High | Microsoft Office Excel | 7.8 | 0.0055 |  |
| [CVE-2026-21258](https://patchblox.com/security/data/cve/CVE-2026-21258.md) | Routine | Microsoft Office Excel | 5.5 | 0.0063 |  |
| [CVE-2026-21261](https://patchblox.com/security/data/cve/CVE-2026-21261.md) | Routine | Microsoft Office Excel | 5.5 | 0.0063 |  |

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Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo