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MEDIUM2026-04-17via TheHackerNews

🚨 Three Microsoft Defender Zero-Days Actively Exploited; Two Still Unpatched Breach — Data Exposed

Three Microsoft Defender Zero-Days Actively Exploited; Two Still Unpatched suffered a data breach. Here's what happened, what data was exposed, and what you should do right now.

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ACCOUNTS
MEDIUM
SEVERITY
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DATA TYPES

What Happened

Huntress is warning that threat actors are exploiting three recently disclosed security flaws in Microsoft Defender to gain elevated privileges in compromised systems.

The activity involves&nbsp;the exploitation of three vulnerabilities that are codenamed BlueHammer (requires GitHub sign-in), RedSun, and UnDefend, all of which were released as zero-days by a researcher known as Chaotic Eclipse (

Impact

  • Affected accounts: Under investigation
  • Data exposed: user data
  • Severity: MEDIUM
  • Source: [TheHackerNews](https://thehackernews.com/2026/04/three-microsoft-defender-zero-days.html)

    • What You Should Do

    If you have an account with Three Microsoft Defender Zero-Days Actively Exploited; Two Still Unpatched, take these steps immediately:

  • **Change your password** — Use a unique, strong password (16+ chars with mixed case, numbers, symbols)
  • **Enable 2FA** — Turn on two-factor authentication if available
  • **Check your email** — Search for breach notifications from Three Microsoft Defender Zero-Days Actively Exploited; Two Still Unpatched
  • **Monitor your accounts** — Watch for unauthorized access on any service where you reused the same password
  • **Scan your site** — If you run a website, [run a free ScanMyVibe scan](https://scanmyvibe.co/scan) to check if your own security headers and configurations protect against common attack vectors

    • Is Your Website Secure?

    Data breaches often exploit weak security configurations — missing Content-Security-Policy headers, misconfigured CORS, exposed API keys. These are exactly the issues ScanMyVibe detects in under 30 seconds.

    [Scan your site free →](https://scanmyvibe.co/scan)

    Timeline

  • 2026-04-17 — Breach reported
  • 2026-04-17 — ScanMyVibe breach alert published
  • Ongoing — Investigation in progress

    • This article is auto-generated by ScanMyVibe's breach monitoring system. Sources are verified but details may evolve as investigations progress. Last updated: 2026-04-17.

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