# KB5001958: September 2021 security update

KB5001958, released September 14, 2021, fixes 1 CVE across 3 products. One of them is being exploited (CVE-2021-38646); 1 on CISA KEV. Patch Radar priority: Patch now. The product is no longer supported.

- Web page: https://patchblox.com/security/fix/microsoft/kb5001958
- Platform: Microsoft
- Released: Sep 14, 2021
- Priority: Patch now (Closes CVE-2021-38646, exploited (CISA KEV, ransomware))
- CVEs: 1, exploited: 1, on CISA KEV: 1
- Vendor advisory: https://support.microsoft.com/help/5001958

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft Office 2013 RT Service Pack 1](https://patchblox.com/security/data/product/microsoft/microsoft-office-2013-rt-service-pack-1.md) |  |  |
| [Microsoft Office 2013 Service Pack 1 (32-bit editions)](https://patchblox.com/security/data/product/microsoft/microsoft-office-2013-service-pack-1-32-bit-editions.md) |  |  |
| [Microsoft Office 2013 Service Pack 1 (64-bit editions)](https://patchblox.com/security/data/product/microsoft/microsoft-office-2013-service-pack-1-64-bit-editions.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2021-38646](https://patchblox.com/security/data/cve/CVE-2021-38646.md) | Patch now | Microsoft Office Access | 7.8 | 0.0799 | CISA KEV, Ransomware |

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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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo