Zero day vulnerability in Microsoft Office Web Components discovered

Microsoft has published an advisory about a serious security vulnerability in its Office Web Components (OWC) software that could allow an attacker to run malicious code on your computer.

Microsoft says it has seen a limited number of attacks exploiting the vulnerability, which specifically lies in the Spreadsheet ActiveX control which can be embedded into webpages.

Affected products include (take a deep breath!) Microsoft Office XP Service Pack 3, Microsoft Office 2003 Service Pack 3, Microsoft Office XP Web Components Service Pack 3, Microsoft Office 2003 Web Components Service Pack 3, Microsoft Office 2003 Web Components for the 2007 Microsoft Office system Service Pack 1, Microsoft Internet Security and Acceleration Server 2004 Standard Edition Service Pack 3, Microsoft Internet Security and Acceleration Server 2004 Enterprise Edition Service…

Read more in my article on the Naked Security website.

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Graham Cluley •   @gcluley

Graham Cluley is a veteran of the cybersecurity industry, having worked for a number of security companies since the early 1990s when he wrote the first ever version of Dr Solomon's Anti-Virus Toolkit for Windows. Now an independent analyst, he regularly makes media appearances and is an international public speaker on the topic of cybersecurity, hackers, and online privacy. Follow him on Twitter, Mastodon, Threads, Bluesky, or drop him an email.