Patch tracker / KB5073724
KB5073724: Windows 10 Version 1809 for 32-bit Sys Security Update (January 2026)
KB5073724 is a Critical security update for Windows 10 Version 1809 for 32-bit Sys, released 2026-01-13. It closes 73 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 73 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.
- Connection and authentication failures in Azure Virtual Desktop and Windows 365
- Apps might become unresponsive when saving files to cloud-based storage
- Some devices with Virtual Secure Mode enabled might fail to shut down or hibernate
KB5073724 is a large rollup fixing 73 CVEs across Windows 11 25H2 (x64 and ARM64) and the older Windows 10 1809, with a top rating of Critical at CVSS 9.8 and one CVE already listed in CISA KEV as actively exploited. The 74% EPSS on the worst issue means exploitation is likely in the wild, and the span from 25H2 down to 1809 means both modern and legacy fleets need this same January batch. No ransomware link is reported for the KEV entry, but exploitation is confirmed regardless.
Do this: Deploy KB5073724 to all Windows 11 25H2 and Windows 10 1809 systems now, prioritizing internet-facing and legacy 1809 hosts because of the actively exploited KEV CVE.
AI-generated from public data, 2026-07-25. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5073724
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5073724
- 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 KB5073724 is installed
Elevated PowerShell. No output means it is not installed.
Known issues, from Microsoft
Quoted from Microsoft's support article for KB5073724 (checked 2026-08-05). Verify against the article before acting.
Connection and authentication failures in Azure Virtual Desktop and Windows 365
Symptoms
After installing this security update, 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.
Resolution
This issue is resolved in Windows updates released on and after January 17, 2026 (such as KB5077796 ). We recommend you install the latest Windows update for your device as it contains important improvements and issue resolutions, including this one.
Apps might become unresponsive when saving files to cloud-based storage
Symptom:
After installing this update, some applications may become unresponsive or encounter unexpected errors when opening or saving files stored in cloud‑based locations. In certain Outlook configurations that store PST files on OneDrive, Outlook may hang and fail to reopen unless the process is terminated or the system is restarted. Users may also see missing sent Items or previously downloaded emails being re‑downloaded.
Workaround:
This issue is addressed in KB5078129
Some devices with Virtual Secure Mode enabled might fail to shut down or hibernate
Symptoms
After installing this update, some Secure Launch -capable PCs with Virtual Secure Mode (VSM) enabled are unable to ...
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.