Microsoft | Daily DMARC News

June 21, 2026
All Three Inbox Giants Now Enforce One-Click Unsubscribe -- and the Deliverability Penalty for Getting It Wrong Is a 3x to 7x Inbox Hit
In February 2024, Google and Yahoo told bulk senders that one-click unsubscribe was no longer optional. Most senders treated it as a Google-and-Yahoo problem and updated their templates accordingly – or believed …
June 18, 2026
Ghost-Sender: Why DMARC Cannot Stop Spoofing When Exchange Online Is Misconfigured
In early June 2026, Swiss cybersecurity firm InfoGuard Labs disclosed a vulnerability they named Ghost-Sender: a misconfiguration in Microsoft Exchange Online that allows an attacker to deliver email impersonating any …
May 29, 2026
8.3 Billion Phishing Threats in Q1 2026: Why CAPTCHA-Gated Attacks and ClickFix Are Reshaping the Email Security Equation
Microsoft Threat Intelligence published its Q1 2026 Email Threat Landscape Report in late April, and the headline figure is difficult to absorb: 8.3 billion email-based phishing threats detected in the first three months …

All Three Inbox Giants Now Enforce One-Click Unsubscribe -- and the Deliverability Penalty for Getting It Wrong Is a 3x to 7x Inbox Hit