Security News > 2021 > September > Microsoft September 2021 Patch Tuesday fixes 2 zero-days, 60 flaws

Today is Microsoft's September 2021 Patch Tuesday, and with it comes fixes for two zero-day vulnerabilities and a total of 60 flaws.
Microsoft has fixed 60 vulnerabilities with today's update, with three classified as Critical, one as Moderate, and 56 as Important.
Soon after Microsoft disclosed the vulnerability, threat actors and security researchers began sharing guides on exploiting the vulnerability, which allowed anyone to start using it in attacks, as demonstrated below.
With the September 2021 Patch Tuesday updates, Microsoft has released a security update for this vulnerability.
September's Patch Tuesday includes fixes for two zero-day vulnerabilities, with the MSHTML bug actively exploited in the wild.
Below is the complete list of resolved vulnerabilities and released advisories in the September 2021 Patch Tuesday updates.
News URL
Related news
- Microsoft March 2025 Patch Tuesday fixes 7 zero-days, 57 flaws (source)
- Patch Tuesday: Microsoft Fixes 57 Security Flaws – Including Active Zero-Days (source)
- Microsoft April 2025 Patch Tuesday fixes exploited zero-day, 134 flaws (source)
- Patch Tuesday: Microsoft Fixes 134 Vulnerabilities, Including 1 Zero-Day (source)
- Choose your own Patch Tuesday adventure: Start with six zero day fixes, or six critical flaws (source)
- April 2025 Patch Tuesday forecast: More AI security introduced by Microsoft (source)
- March 2025 Patch Tuesday forecast: A return to normalcy (source)
- Apple Releases Patch for WebKit Zero-Day Vulnerability Exploited in Targeted Attacks (source)
- URGENT: Microsoft Patches 57 Security Flaws, Including 6 Actively Exploited Zero-Days (source)
- Microsoft patches Windows Kernel zero-day exploited since 2023 (source)