Security News > 2021 > April > Microsoft April 2021 Patch Tuesday fixes 108 flaws, 5 zero-days

Today is Microsoft's April 2021 Patch Tuesday, and with it comes five zero-day vulnerabilities and more Critical Microsoft Exchange vulnerabilities.
With today's update, Microsoft has fixed 108 vulnerabilities, with 19 classified as Critical and 89 as Important.
To make matters worse, Microsoft fixed four critical Microsoft Exchange vulnerabilities that the NSA discovered.
As part of today's Patch Tuesday, Microsoft has fixed four publicly disclosed vulnerabilities and one actively exploited vulnerability.
Microsoft Exchange admins are not getting any rest as four more Critical remote code execution vulnerabilities discovered by the NSA were fixed in Microsoft Exchange today.
Below is the full list of resolved vulnerabilities and released advisories in the April 2021 Patch Tuesday updates.
News URL
Related news
- Microsoft January 2025 Patch Tuesday fixes 8 zero-days, 159 flaws (source)
- Microsoft February 2025 Patch Tuesday fixes 4 zero-days, 55 flaws (source)
- Patch Tuesday: Microsoft Patches Two Actively Exploited Zero-Day Flaws (source)
- Week in review: Exploited Ivanti Connect Secure zero-day, Patch Tuesday forecast (source)
- February's Patch Tuesday sees Microsoft offer just 63 fixes (source)
- Microsoft’s Patch Tuesday Fixes 63 Flaws, Including Two Under Active Exploitation (source)
- January 2025 Patch Tuesday forecast: Changes coming in cybersecurity guidance (source)
- Microsoft fixes actively exploited Windows Hyper-V zero-day flaws (source)
- 3 Actively Exploited Zero-Day Flaws Patched in Microsoft's Latest Security Update (source)
- Patch Tuesday: January 2025 Security Update Patches Exploited Elevation of Privilege Attacks (source)