Microsoft Issues Emergency Windows Updates for Compromised eMudhra Certificates
First merged summary.
Microsoft released emergency Windows updates on October 26, 2026, to revoke trust in eight compromised eMudhra intermediate keys.
Microsoft released an out-of-band Windows update on October 26, 2026, removing seven certificates tied to eight recoverable eMudhra intermediate CA private keys that were exposed. Six keys relate to TLS and two to code signing, potentially allowing an attacker to impersonate sites or sign trusted software. Microsoft says its own systems were not affected and that the keys could be used for malicious purposes but no attacks are confirmed. Edge received matching removals on October 27, while a CRLSet update blocks affected TLS certificates in Edge and WebView2 without a new browser version. Disconnected Windows systems and Azure virtual machines require an alternate update path.
- Eight eMudhra intermediate private keys exposed
- Six for TLS, two for code signing
- October 26, 2026: Out-of-band Windows update removes seven certificates
- October 20, 2026: Authorities blocked via Disallowed Certificate Trust List
- Edge trust list updated October 27, 2026
- CRLSet blocks affected TLS certificates in Edge and WebView2
What each outlet adds
beyond the shared facts- Cyber Security NewsCRLSet update for Edge and WebView2; alternate path for disconnected systems
- Products
- WindowsMicrosoft EdgeWebView2
- Organizations
- Microsoft Security Response Center
Coverage
oldest first · one row per article · UTC- · 6d ago
Cyber Security NewsFirst report
Microsoft emergency updates block compromised eMudhra certificates
Eight recoverable intermediate keys could forge TLS or code-signing certificates; Microsoft says its own systems were not affected.
- · 6d ago
GBHackers
Microsoft revokes trust in compromised eMudhra certificates
An October 26 Windows update drops seven certificates after weak key generation exposed eight eMudhra intermediate keys.