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Microsoft Office Zero-Day (CVE-2026-21509)


dips
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  • On the path to Greatness

Just a heads up, there is a Zero Day in Microsoft Office. 

More info: 

The good news is that if running Office 2021 and later, only a restart of Office Apps is required to mitigate the issue.

Anything older will need Registry entries set:

CVE-2026-21509 - Security Update Guide - Microsoft - Microsoft Office Security Feature Bypass Vulnerability

5 comments

coolsport00
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Thanks for sharing Dipen. Thankfully..it appears only a restart is needed for me & my org. 🙌🏻

Hope you’re well!


Chris.Childerhose
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Wow a zero day for Office.   Time to check and do what is required to mitigate it.


CMF
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  • Veeam Legend
  • January 28, 2026

Thanks for sharing Dipen. 


dips
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  • Author
  • On the path to Greatness
  • February 3, 2026

Thanks for sharing Dipen. Thankfully..it appears only a restart is needed for me & my org. 🙌🏻

Hope you’re well!

Hey Shane, 

All good thank you! I’ve been MIA due to other commitments but hoping to come back once things calm down. 

Hope you are keeping well!

Dipen


coolsport00
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Hopefully things calm down for you soon. Yessir...I’m doing well. Thank you for asking.

Best.