Patch tracker / CVE reference / CVE-2026-34337
CVE-2026-34337
Updated July 21, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.
Critical severity Microsoft vulnerability, CVSS 9.8. Fixed by 12 Microsoft security updates.
All about CVE-2026-34337: the Senserva AI read, whether it is exploited, the official patches, its change history, and the questions admins ask.
CVE-2026-34337 is a critical severity Microsoft vulnerability with a CVSS score of 9.8. Its EPSS score puts the probability of exploitation in the next 30 days at 72%. Microsoft has shipped the fix: deploy one of the 12 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.
Risk summary
Senserva provides Three Free Unlimited Audits, including all tenants and full Claude MCP.Start my Audit
Senserva AI Opinion for CVE-2026-34337
ARM64 coverage distinguishes this Cloud Files Mini Filter Driver escalation, which affects Windows Server 2022 including Server Core and Windows 10 21H2 for ARM64. It carries the Critical (CVSS 9.8) rating and 72 percent EPSS exploit probability common to this cycle's cloud files flaws. ARM64 Windows devices are a growing but often untracked slice of fleets, and their patch compliance is frequently invisible in tooling built for x64.
Do this: Confirm your patch reporting actually includes ARM64 Windows devices, then verify this update reached them and the Server 2022 hosts.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2026-34337
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2026-34337
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 72%. CVSS 9.8 (Critical).
This CVE is among the top 25% of tracked Microsoft CVEs by EPSS exploit probability.
Official patch(es) for CVE-2026-34337
High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5087420, KB5087423, KB5087424, KB5087538, KB5087539, KB5087541, KB5087544, KB5087545, KB5089466, KB5089549, KB5093998, KB5094127 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.
Apply the Microsoft security updates below to fix CVE-2026-34337. 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-2026-34337
Is CVE-2026-34337 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 72%.
What patch fixes CVE-2026-34337?
Microsoft fixed CVE-2026-34337 in KB5087420, KB5087423, KB5087424, KB5087538, KB5087539, KB5087541, KB5087544, KB5087545, KB5089466, KB5089549, KB5093998, KB5094127. Download from the Microsoft Update Catalog, or let Intune, Windows Update, or WSUS deliver it.
Which products are affected by CVE-2026-34337?
Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows Server 2019, Windows Server 2025 (Server Core installation).
Can I ask my own AI about CVE-2026-34337?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-34337'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 three times a day (5 AM, 12:30 PM, and 7 PM US Central).
Fixed by the same updates
If you are patching CVE-2026-34337, the same updates also fix these:
Authoritative references
Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.
