Patch tracker / KB5103213
KB5103213: Microsoft Exchange Server Subscription Security Update (July 2026)
KB5103213 is a Critical security update for Microsoft Exchange Server Subscription, released 2026-07-14. It closes 4 CVEs with a maximum CVSS of 9.6. Get it from the Microsoft Update Catalog below, and see where it sits against the rest of the month on the patch tracker.
Microsoft security update released 2026-07-14. Fixes 4 CVEs.
No exploitation is confirmed for the CVEs in this update and the EPSS exploitation probability is currently 1.6%. 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.
Exchange Server updates are their own discipline: they install on the servers themselves (Windows Update, Microsoft Update, or the downloaded package run as administrator), not through Intune device policies. The install guidance below covers the Exchange path. 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.
Updated July 25, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Download KB5103213
Get the official update for KB5103213. The download and file size for each supported product are on the Microsoft Update Catalog page.
Update summary
Senserva AI Opinion for KB5103213
KB5103213 is a Security Update for Exchange Server 2019 Cumulative Update 15, shipped in the July 2026 Patch Tuesday cycle. The per-update CVE breakdown is still provisional because Microsoft has not published the detail for this cycle, and the release document maps no named zero-days here. Exchange remains a high-value target regardless of headline severity, so any on-premises mailbox server running CU15 is in scope even without a confirmed critical flaw yet.
Do this: Stage KB5103213 on a non-production Exchange 2019 CU15 server now and confirm the CVE detail once Microsoft publishes it before scheduling the production rollout.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5103213
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5103213
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 4 CVEs. Most severe CVSS 9.6 (Critical). EPSS exploit probability up to 1.6%.
Among the lower half of tracked Microsoft updates by EPSS exploit probability.
What to do
Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. Senserva flags whether KB5103213 is missing on your devices.
Check if KB5103213 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.
Known issues
Microsoft's support article for KB5103213 lists no known issues as of 2026-07-21. Check the article before broad deployment; Microsoft updates it as reports come in.
Writing about KB5103213? 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-2026-55005 | Critical | 9.6 | 1.6% | No |
| CVE-2026-55006 | Critical | 9.6 | 1.6% | No |
| CVE-2026-55008 | Critical | 9.6 | 1.6% | No |
| CVE-2026-55009 | Critical | 9.6 | 1.6% | No |
What the press says about this update
Trusted-source coverage of the CVEs this update fixes, pulled live from their own feeds.
Affected products
Also released in July 2026
The highest-risk updates from the same release:
The full month, summarized: Microsoft Patch Tuesday.
How to install KB5103213
This is an Exchange Server security update. It installs on each Exchange server, not through client update rings:
- Windows Update / Microsoft Update on the server offers Exchange security updates when enabled.
- Manual install: download from the Update Catalog above and run the package from an elevated prompt (running it without elevation is the classic cause of a broken install).
- Verify afterward with Microsoft's Exchange Server Health Checker script, and confirm the build number matches the update.
Common questions about KB5103213
Does KB5103213 have known issues?
Microsoft's support article for KB5103213 lists no known issues as of 2026-07-21. Check the article before broad deployment; Microsoft updates it as reports come in.
Is KB5103213 urgent?
KB5103213 is rated Critical with a maximum CVSS of 9.6. No active exploitation is confirmed yet, so schedule it in your prompt patch cycle.
How do I download KB5103213?
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 KB5103213 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 KB5103213?
Yes. This page includes a free, ready-to-paste AI prompt containing KB5103213'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 twice a day (5 AM and 3 PM US Central).
Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.
