Patch tracker / CVE reference / CVE-2025-59206
CVE-2025-59206
CVE-2025-59206 is a critical severity Microsoft vulnerability with a CVSS score of 9.9. Microsoft has shipped the fix: deploy the update below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Critical severity Microsoft vulnerability, CVSS 9.9. Fixed by 1 Microsoft security update.
Risk summary
Updated July 25, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Senserva AI Opinion for CVE-2025-59206
This ReFS Deduplication Service elevation-of-privilege flaw rates Critical 9.9 with a 6 percent EPSS score on Windows 11 25H2 and Server 2025 Server Core. The dedup service runs with high privilege on storage volumes, so a bug there is a valuable local-escalation target on file servers. Severity is at the top of the scale even as modeled exploitation stays low. It is not in CISA KEV.
Do this: Update Server 2025 Core and Windows 11 25H2 hosts running ReFS deduplication and restrict who can log on locally to those storage systems.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2025-59206
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2025-59206
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
Exploitation and severity
Not in the CISA KEV catalog. EPSS exploit probability 6.0%. CVSS 9.9 (Critical).
This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2025-59206
Elevated priority: high severity or a meaningful exploitation probability, sooner if an affected product is internet-facing. In Intune or Defender, confirm whether the fixing update KB5066835 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security update below to fix CVE-2025-59206. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.
Affected products
Common questions about CVE-2025-59206
Is CVE-2025-59206 actively exploited?
It is not currently listed in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score puts the probability of exploitation in the next 30 days at 6.0%.
What patch fixes CVE-2025-59206?
Microsoft fixed CVE-2025-59206 in KB5066835. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2025-59206?
Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019.
Can I ask my own AI about CVE-2025-59206?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2025-59206's key facts: severity, CVSS, EPSS exploit probability, CISA KEV status, and the fixing KB. Copy it into Claude, ChatGPT, or Copilot for a triage plan; the data is refreshed twice a day (5 AM and 3 PM US Central).
Fixed by the same update
If you are patching CVE-2025-59206, the same update also fixes these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.
