Patch tracker / KB5074109
KB5074109: Windows 10 Version 1809 for 32-bit Sys Security Update (January 2026)
KB5074109 is a Critical security update for Windows 10 Version 1809 for 32-bit Sys, released 2026-01-13. It closes 86 CVEs with a maximum CVSS of 9.8. At least one of them is actively exploited (CISA KEV), so this is a deploy-first update. The most likely of them to be attacked is CVE-2026-20962, which FIRST.org rates at 75% probability of exploitation in the next 30 days.
Update summary
Fixes 86 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 75%. Among the top 10% of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Windows 11 Version 25H2 for x64-based Systems has shipped since this one: KB5087423 (2026-06-09). 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 documents 3 known issues with this update.
- Password icon might be missing or invisible in the lock screen sign-in options
- Connection and authentication failures in Azure Virtual Desktop and Windows 365
- Apps might become unresponsive when saving files to cloud-based storage
KB5074109 is a large rollup fixing 86 CVEs across Windows 11 25H2 and the older Windows 10 1809, with a Critical CVSS 9.8 flaw and one CVE already listed in CISA KEV as actively exploited. The 74% EPSS score signals that at least one of these vulnerabilities has a high likelihood of exploitation in the near term, though none are currently tied to ransomware campaigns. The mix of a cutting-edge OS version and legacy 1809 means both modern and lagging estates are exposed by the same update.
Do this: Deploy KB5074109 to all Windows 11 25H2 and Windows 10 1809 systems now, prioritizing internet-facing hosts given the KEV-listed CVE.
AI-generated from public data, 2026-07-25. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5074109
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5074109
- Released
- 2026-01-13
- Last changed
- 2026-08-04
- Changes tracked
- 3
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 KB5074109 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5074109 (checked 2026-08-05). Verify against the article before acting.
Password icon might be missing or invisible in the lock screen sign-in options
Symptoms
After installing the August 2025 non-security preview update ( KB5064081 ) or later updates, you might notice that the password icon is not visible in the sign-in options on the lock screen. If you hover over the space where the icon should appear, you’ll see that the password button is still available. Select this placeholder to open the password text box and enter your password. After entering your password, you can sign in normally.
Individuals using Windows Home or Pro editions on personal devices are very unlikely to experience this issue. This issue primarily affects enterprise or managed IT environments.
Workaround
This issue is addressed in KB5074105 .
Connection and authentication failures in Azure Virtual Desktop and Windows 365
Symptoms
After installing the January 2026 security update ( KB5074109 ), released on January 13, 2026, credential prompt failures occurred during Remote Desktop connections using the Windows App on Windows client devices, impacting Azure Virtual Desktop and Windows 365. The issue affects Windows App on specific Windows builds, causing sign-in failures.
Workaround
This issue is addressed in KB5077744 .
Apps might become unresponsive when saving files to cloud-based storage
Symptom :
After installing this update, some applications may become unresponsive or ...
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.
Scope and sources
- Affected products
- Also released in January 2026
KB5002822
6 CVEs · Critical · exploitedKB5002825
7 CVEs · Critical · exploitedKB5002828
7 CVEs · Critical · exploitedKB5073379
86 CVEs · Critical · exploitedKB5073450
80 CVEs · Critical · exploitedKB5073455
80 CVEs · Critical · exploitedKB5073457
78 CVEs · Critical · exploitedKB5073722
54 CVEs · Critical · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.