Microsoft Defender Misclassifies DigiCert Root Certificates as Malware

TL;DR
Microsoft Defender’s late-April 2026 signature update wrongly flagged two DigiCert root certificates as malware (Trojan:Win32/Cerdigent.A!dha), quarantining their entries in Windows’ AuthRoot/Certificates store and risking SSL/TLS validation and code-signing for enterprise software. A corrective definition update (.430) began restoring the certificates, with automatic remediation rolling out and admins advised to verify restoration via certutil and Advanced Hunting logs. This incident underscores the risks of false positives in automated security responses targeting core Windows components.
Topics:technologycyber-security#cyber-security#digicert#false-positive#microsoft-defender#root-certificates#ssltls
- Microsoft Defender Mistakenly Flags DigiCert Root Certificates as Malware CyberSecurityNews
- DigiCert hacked with a malicious screensaver file Risky Business Newsletters
- Microsoft Defender flagging "Cerdigent" trojan malware on Windows 11, Server PCs worldwide Neowin
- Microsoft Defender mistakenly flags trusted DigiCert certificates as malware PiunikaWeb
- Microsoft Defender wrongly flags DigiCert certs as Trojan:Win32/Cerdigent.A!dha BleepingComputer
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