# KB5121573: August 2026 security update

KB5121573, released August 11, 2026, fixes 7 CVEs in Microsoft Exchange Server Subscription Edition RTM. None of them is reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/fix/microsoft/kb5121573
- Platform: Microsoft
- Released: Aug 11, 2026
- Priority: Urgent (Closes CVE-2026-62911, rated Critical)
- CVEs: 7, exploited: 0, on CISA KEV: 0
- Vendor advisory: https://support.microsoft.com/help/5121573

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [Microsoft Exchange Server Subscription Edition RTM](https://patchblox.com/security/data/product/microsoft/microsoft-exchange-server-subscription-edition-rtm.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-62911](https://patchblox.com/security/data/cve/CVE-2026-62911.md) | Urgent | Microsoft Exchange Server | 8.0 | 0.0069 |  |
| [CVE-2026-62910](https://patchblox.com/security/data/cve/CVE-2026-62910.md) | High | Microsoft Exchange Server | 7.2 | 0.0100 |  |
| [CVE-2026-62913](https://patchblox.com/security/data/cve/CVE-2026-62913.md) | High | Microsoft Exchange Server | 8.8 | 0.0091 |  |
| [CVE-2026-62914](https://patchblox.com/security/data/cve/CVE-2026-62914.md) | High | Microsoft Exchange Server | 7.3 | 0.0045 |  |
| [CVE-2026-62912](https://patchblox.com/security/data/cve/CVE-2026-62912.md) | Routine | Microsoft Exchange Server | 6.5 | 0.0198 |  |
| [CVE-2026-65813](https://patchblox.com/security/data/cve/CVE-2026-65813.md) | Routine | Microsoft Exchange Server | 6.5 | 0.0094 |  |
| [CVE-2026-62915](https://patchblox.com/security/data/cve/CVE-2026-62915.md) | Routine | Microsoft Exchange Server | 6.5 | 0.0064 |  |

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo