Breach404
Back to Insights
Cybersecurity2 min readApril 16, 2026

ThreatsDay Bulletin: Defender 0-Day, SonicWall Brute-Force, 17-Year-Old Excel RCE and 15 More Stories

Multiple critical vulnerabilities are currently under active exploit, including a zero-day in Microsoft Defender, brute-force attacks targeting SonicWall appliances, and a 17-year-old remote code execution flaw in Excel that remains dangerous despite its

Could your website be vulnerable to attacks like this?

Run a free 10-point security scan on your site — headers, SSL, DNS, and more. Results in 15 seconds.

Test Your Site Now — It's Free