Security News > 2021 > November > Microsoft November 2021 Patch Tuesday fixes 6 zero-days, 55 flaws
Today is Microsoft's November 2021 Patch Tuesday, and with it comes fixes for six zero-day vulnerabilities and a total of 55 flaws.
The actively exploited vulnerabilities are for Microsoft Exchange and Excel, with the Exchange zero-day used as part of the Tianfu hacking contest.
Microsoft has fixed 55 vulnerabilities with today's update, with six classified as Critical and 49 as Important.
November's Patch Tuesday includes fixes for six zero-day vulnerabilities, two actively exploited against Microsoft Exchange and Microsoft Excel.
The Microsoft Excel CVE-2021-42292 was discovered by the Microsoft Threat Intelligence Center and has been actively used in malicious attacks.
Below is the complete list of resolved vulnerabilities and released advisories in the November 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)
Related Vulnerability
| DATE | CVE | VULNERABILITY TITLE | RISK |
|---|---|---|---|
| 2021-11-10 | CVE-2021-42292 | Unspecified vulnerability in Microsoft products Microsoft Excel Security Feature Bypass Vulnerability | 0.0 |