Security News > 2021 > January > Microsoft January 2021 Patch Tuesday fixes 83 flaws, 1 zero-day
Today is Microsoft's January 2021 Patch Tuesday, and it is the first Microsoft security update release in 2021, so please be very nice to your Windows administrators today.
With the January 2021 Patch Tuesday security updates release, Microsoft has released fixes for 83 vulnerabilities, with ten classified as Critical and 73 as Important.
Microsoft fixed both a zero-day and a publicly disclosed vulnerability as part of the January 2021 security updates.
Microsoft also patched a publicly disclosed Microsoft splwow64 Elevation of Privilege vulnerability tracked as CVE-2021-1648.
Microsoft has not released an official patch for this vulnerability.
Below is the full list of resolved vulnerabilities and released advisories in the January 2021 Patch Tuesday updates.
News URL
Related news
- Microsoft April 2025 Patch Tuesday fixes exploited zero-day, 134 flaws (source)
- Patch Tuesday: Microsoft Fixes 134 Vulnerabilities, Including 1 Zero-Day (source)
- April 2025 Patch Tuesday forecast: More AI security introduced by Microsoft (source)
- New Windows zero-day leaks NTLM hashes, gets unofficial patch (source)
- Zero-Day Alert: Google Releases Chrome Patch for Exploit Used in Russian Espionage Attacks (source)
- Week in review: Probing activity on Palo Alto Networks GlobalProtect portals, Patch Tuesday forecast (source)
- Microsoft: Windows CLFS zero-day exploited by ransomware gang (source)
- Microsoft fixes actively exploited Windows CLFS zero-day (CVE-2025-29824) (source)
- April's Patch Tuesday leaves unlucky Windows Hello users unable to login (source)
- Emergency patch for potential SAP zero-day that could grant full system control (source)
Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2021-01-12 | CVE-2021-1648 | Improper Privilege Management vulnerability in Microsoft products Microsoft splwow64 Elevation of Privilege Vulnerability | 0.0 |