IIJ: data leakage from IIJ Secure MX Service

Attackers exploited a previously unknown Active! mail vulnerability. The first notice identified up to 6,493 contracts and 4,072,650 email accounts as potentially exposed. The April 22 report confirmed leakage across 586 distinct contracts, including information for 311,288 email accounts. Email contents/headers and credentials for linked cloud services were also affected.