Patch tracker / KB5050674
KB5050674: Microsoft Exchange Server Subscription Security Update (August 2025)
KB5050674 is a High security update for Microsoft Exchange Server Subscription, released 2025-08-12. It closes 1 CVE with a maximum CVSS of 8.0. The most likely of them to be attacked is CVE-2025-53786, which FIRST.org rates at 7% probability of exploitation in the next 30 days.
Update summary
Fixes 1 CVE. Most severe CVSS 8.0 (High). EPSS exploit probability up to 7.4%. Among the top half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Microsoft Exchange Server Subscription Edition RTM has shipped since this one: KB5121573 (2026-08-11). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.
KB5050674 addresses CVE-2025-53786, a High severity (CVSS 8.0) flaw affecting on-premises Exchange Server Subscription Edition RTM, Exchange 2019 CU15, and Exchange 2016 CU23. This targets hybrid Exchange deployments where the on-prem and Exchange Online trust relationship can be abused to escalate privileges into the connected cloud tenant. It is not in CISA KEV and has a modest 7% EPSS, but the hybrid attack path makes it consequential for organizations still running coexistence with Exchange Online.
Do this: Apply KB5050674 to your on-premises Exchange servers and follow Microsoft's hybrid hardening guidance to rotate or reset the shared service principal keys after patching.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5050674
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5050674
- Released
- 2025-08-12
- Last changed
- 2025-08-12
- Changes tracked
- 1
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.
Check if KB5050674 is installed
Elevated PowerShell. No output means it is not installed.
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-2025-53786 | High | 8.0 | 7.4% | No |
Scope and sources
- Affected products
- Also released in August 2025
KB5058379
36 CVEs · High · exploitedKB5058383
39 CVEs · High · exploitedKB5058384
44 CVEs · High · exploitedKB5058385
42 CVEs · High · exploitedKB5058387
33 CVEs · High · exploitedKB5058392
42 CVEs · High · exploitedKB5058405
38 CVEs · High · exploitedKB5058411
44 CVEs · High · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.