Patch tracker / KB5091223
KB5091223: Microsoft SQL Server 2025 for x64-base Security Update (May 2026)
Updated July 21, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
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Microsoft security update released 2026-05-12. Fixes 1 CVE.
All about KB5091223: the download, the Senserva AI read, a PowerShell installed-check, install guidance, the CVEs it fixes, and its change history.
KB5091223 is a High security update for Microsoft SQL Server 2025 for x64-base, released 2026-05-12. It closes 1 CVE with a maximum CVSS of 8.8. Get it from the Microsoft Update Catalog below, and see where it sits against the rest of the month on the patch tracker.
No exploitation is confirmed for the CVEs in this update and the EPSS exploitation probability is currently <1%. That can change: CVEs from past updates regularly get exploited months later, which is why deploying on your normal cadence, without exceptions that linger, is what keeps this one boring.
SQL Server updates deploy per instance, usually via the downloaded package or your server patching tool rather than client update rings. The install guidance below covers the options. For the bigger picture: how the Microsoft patching tools fit together, this month's Patch Tuesday summary, and every update ranked by real-world risk.
Download KB5091223
Get the official update for KB5091223. The download and file size for each supported product are on the Microsoft Update Catalog page.
Update summary
Senserva AI Opinion for KB5091223
KB5091223 patches a single flaw (CVE-2026-40370) across three SQL Server generations at once: 2025 CU4, 2022 CU24, and 2017 GDR. At CVSS 8.8 High severity it is likely a code execution or privilege escalation path reachable by an authenticated connection, though EPSS is still only 1% and it is not in CISA KEV. The unusual part is the spread across old and new SQL Server builds, so any database host you run is probably in scope.
Do this: Inventory every SQL Server 2017, 2022, and 2025 instance and apply the matching branch (GDR for 2017, CU24 for 2022, CU4 for 2025) starting with internet-reachable or multi-tenant database servers.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5091223
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5091223
Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.
Exploitation and severity
Fixes 1 CVE. Most severe CVSS 8.8 (High). EPSS exploit probability up to <1%.
Among the lower half of tracked Microsoft updates by EPSS exploit probability.
What to do
Moderate priority: schedule it in your normal patch cycle. Senserva flags whether KB5091223 is missing on your devices.
Check if KB5091223 is installed
Copy-paste PowerShell: one machine, or your whole fleet in one pass. No output means the update is not installed.
Get-HotFix covers Windows updates. Office, SharePoint, and Exchange server updates show under installed updates in Programs and Features, or check the Update Catalog history.
Writing about KB5091223? Cite this page
Copy-paste for a blog post, forum answer, or internal doc. The link always carries the current risk data.
CVEs fixed by this update
Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.
| CVE | Severity | CVSS | EPSS | Exploited |
|---|---|---|---|---|
| CVE-2026-40370 | High | 8.8 | <1% | No |
Affected products
Also released in May 2026
The highest-risk updates from the same release:
The full month, summarized: Microsoft Patch Tuesday.
How to install KB5091223
This is a SQL Server update. It deploys per instance:
- Manual or scripted install of the package from the Update Catalog above, instance by instance, starting with test.
- Microsoft Update can offer SQL Server updates when the machine opts in to updates for other Microsoft products.
- Verify afterward by checking the instance build number against the update's target build.
Common questions about KB5091223
Is KB5091223 urgent?
KB5091223 is rated High. Include it in your normal patch cycle unless your environment raises its priority.
How do I download KB5091223?
From the Microsoft Update Catalog (linked on this page), or let Intune, Windows Update for Business, Windows Autopatch, or WSUS deliver it. The catalog page lists the download for each supported product.
How do I deploy KB5091223 with Intune?
Assign a Windows Update ring (quality update policy) to the device groups and the update flows on the ring's deferral schedule. For urgent updates, Intune expedite policies can bypass the ring deferrals. Verify the rollout with update compliance reporting rather than assuming delivery.
Can I ask my own AI about KB5091223?
Yes. This page includes a free, ready-to-paste AI prompt containing KB5091223's key facts: severity, CVE count, exploitation status, and the download link. Copy it into Claude, ChatGPT, or Copilot for a rollout plan; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).
Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.
