Patch tracker / CVE reference / CVE-2026-42828

CVE-2026-42828

CVE-2026-42828 is a Microsoft vulnerability that Microsoft rates Important, with a CVSS score of 7.8 (High). Microsoft has shipped the fix: deploy one of the 7 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

2.6%

EPSS, 30 days

High

Severity

Not in the CISA KEV catalog. EPSS exploit probability 2.6%. CVSS 7.8 (High).

This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.

Senserva AI Opinion for CVE-2026-42828

The Windows Projected File System, the virtualization layer behind features like sparse repo checkouts, carries a Critical (CVSS 9.8) elevation of privilege flaw on Windows Server 2022, Server 2019 Server Core, and Windows 10 Version 1809. ProjFS runs in the kernel, so a successful exploit converts local user access into full control of the host. EPSS gives it a 48 percent chance of exploitation, with no KEV listing or ransomware use yet.

Do this: Patch Server 2022 and Server 2019 hosts where ProjFS is enabled first, and check whether the feature is even needed on the rest.

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

Senserva AI Opinion and rich prompt for CVE-2026-42828

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-2026-42828 (source: https://senserva.com/cve/CVE-2026-42828.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed daily (early morning US Central)):
- CVE-2026-42828: Microsoft vulnerability, Microsoft rating Important, CVSS 7.8 (High)
- EPSS 30-day exploitation probability: 2.6%
- Actively exploited (CISA KEV): no
- Fixed by: KB5093998, KB5094123, KB5094125, KB5094126, KB5094127, KB5094128, KB5095051
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.

Schedule normally

No exploitation observed as of 2026-10-14: not in the CISA KEV catalog, EPSS 3%.

Fixed by KB5093998 and 6 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Deploy with your normal update cycle. This page refreshes daily; the verdict changes the day the data does.

Official patch(es) for CVE-2026-42828

Moderate priority: schedule it in your normal patch cycle. In Intune or Defender, confirm whether the fixing updates KB5093998, KB5094123, KB5094125, KB5094126, KB5094127, KB5094128, KB5095051 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-2026-42828. 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.

KB5093998 KB5094123 KB5094125 KB5094126 KB5094127 KB5094128 KB5095051

Scope and sources

Affected products

Fixed by the same updates

CVE-2025-54518 CVE-2026-41096 CVE-2026-42990 CVE-2026-44815 CVE-2026-45657 CVE-2026-47291 CVE-2026-42904 CVE-2025-10263

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.