Patch tracker / CVE reference / CVE-2026-20940

CVE-2026-20940

CVE-2026-20940 is a Microsoft vulnerability that Microsoft rates Important, with a CVSS score of 7.8 (High). Its EPSS score puts the probability of exploitation in the next 30 days at 71%. Microsoft has shipped the fix: deploy one of the 11 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

High

7.8

CVSS v3

71%

EPSS, 30 days

High

Severity

Not in the CISA KEV catalog. EPSS exploit probability 71%. CVSS 7.8 (High).

This CVE is among the top 10% of tracked Microsoft CVEs by EPSS exploit probability.

Senserva AI Opinion for CVE-2026-20940

CVE-2026-20940 is an elevation of privilege flaw in the Windows Cloud Files Mini Filter Driver, the component behind OneDrive and other on demand cloud sync. It carries a Critical rating with a CVSS score of 9.8 and a 74 percent EPSS exploit probability, unusually high for a local privilege escalation, and it affects Windows 10 22H2 on 32-bit plus Windows 11 23H2 on ARM64 and x64. It is not yet in CISA KEV or tied to ransomware, but the high EPSS suggests attackers are likely to weaponize it soon.

Do this: Deploy Microsoft's patch for CVE-2026-20940 to all Windows 10 22H2 and Windows 11 23H2 systems now, prioritizing shared and multi user endpoints where local access is easiest.

AI-generated from public data, 2026-07-26. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2026-20940

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

I am an IT admin assessing a vulnerability. Facts for CVE-2026-20940 (source: https://senserva.com/cve/CVE-2026-20940.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed daily (early morning US Central)):
- CVE-2026-20940: Microsoft vulnerability, Microsoft rating Important, CVSS 7.8 (High)
- EPSS 30-day exploitation probability: 71%
- Actively exploited (CISA KEV): no
- Fixed by: KB5073455, KB5073457, KB5073695, KB5073696, KB5073697, KB5073698, KB5073699, KB5073700, KB5073722, KB5073723, KB5073724
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) What to patch or mitigate first. 4) How to check whether my devices are exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch this cycle

Not confirmed exploited yet, but the 30-day exploit probability is high (EPSS 71%).

Fixed by KB5073455 and 10 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Patch in this maintenance window; do not let it slip to the next one.

Official patch(es) for CVE-2026-20940

High priority: EPSS puts the odds of near-term exploitation high. In Intune or Defender, confirm whether the fixing updates KB5073455, KB5073457, KB5073695, KB5073696, KB5073697, KB5073698, KB5073699, KB5073700, KB5073722, KB5073723, KB5073724 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-2026-20940. 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.

KB5073455 KB5073457 KB5073695 KB5073696 KB5073697 KB5073698 KB5073699 KB5073700 KB5073722 KB5073723 KB5073724

Scope and sources

Affected products

Fixed by the same updates

CVE-2026-20805 CVE-2025-6965 CVE-2026-20868 CVE-2026-20856 CVE-2026-20931 CVE-2023-31096 CVE-2024-55414 CVE-2026-20809

Authoritative references

Official CVE record (cve.org)NVD detail Microsoft MSRC FIRST.org EPSS

Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.