🛡️ **Russian State Actors Exploit Zimbra Zero-Day in Active Phishing Campaign — All ZCS Deployments at Immediate Risk**
Published Thursday, July 23, 2026 at 09:02 AM PT BLUF: Russian state-sponsored cyber actors are actively exploiting CVE-2025-66376, a zero-day vulnerability in Zimbra Collaboration Suite (ZCS), via phishing campaigns to compromise user accounts. The attack chain leverages pass-the-cookie techniques for post-exploitation access. Organizations running ZCS must immediately patch or isolate affected instances; credentials for ZCS-authenticated users should be treated as potentially compromised. ...