Patch tracker / KB5059086

KB5059086: Microsoft Dynamics 365 version 9.1 Security Update (August 2025)

KB5059086 is a Medium security update for Microsoft Dynamics 365 version 9.1, released 2025-08-12. It closes 1 CVE with a maximum CVSS of 5.4. It is the 60th largest of the 67 updates Microsoft shipped that month, by CVEs closed.

Update summary

Medium
2025-08-12
Released
1
CVEs fixed
5.4
Max CVSS v3
Medium
Severity
Deploy this cycle
Fixes 1 CVE for Microsoft Dynamics 365 version 9.1. No confirmed in-the-wild exploitation in this set today.

Fixes 1 CVE. Most severe CVSS 5.4 (Medium). EPSS exploit probability up to <1%. Among the lower half of tracked Microsoft updates by EPSS exploit probability.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for Microsoft Dynamics 365 (on-premises) version 9.1 has shipped since this one: KB5078943 (2026-05-12). 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.

Microsoft Update Catalog: download KB5059086Microsoft support article
Senserva AI Opinion for KB5059086

KB5059086 patches CVE-2025-49745, a single Medium severity flaw (CVSS 5.4) in Dynamics 365 on-premises version 9.1. Only organizations still running the self-hosted 9.1 build are exposed, and with an EPSS of 1 percent and no listing in CISA KEV or ransomware campaigns, active exploitation is not currently indicated. It matters because on-premises Dynamics servers are often patched on slower cycles than cloud tenants, leaving this fix easy to overlook.

Do this: Schedule KB5059086 for your on-premises Dynamics 365 version 9.1 servers during the next maintenance window since no urgent exploitation pressure exists.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5059086

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

Full tracking and change history for KB5059086

Released
2025-08-12
Last changed
2026-07-13
Changes tracked
2

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 KB5059086 is installed

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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.

CVESeverityCVSSEPSSExploited
CVE-2025-49745Medium5.4<1%No

Scope and sources

Affected products
Also released in August 2025

KB5058379

36 CVEs · High · exploited

KB5058383

39 CVEs · High · exploited

KB5058384

44 CVEs · High · exploited

KB5058385

42 CVEs · High · exploited

KB5058387

33 CVEs · High · exploited

KB5058392

42 CVEs · High · exploited

KB5058405

38 CVEs · High · exploited

KB5058411

44 CVEs · High · exploited

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5059086 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
Provided as is, without warranty; verify against the vendor advisory before acting. Data notice and terms.