A fix for a critical Zimbra email server flaw was available for more than three weeks before the public was told about it, and attackers used that time. Microsoft Threat Intelligence reports that threat actors exploited CVE-2026-73570 (CVSS 8.9), an unauthenticated operating system command injection vulnerability in the Zimbra Collaboration Suite, for weeks before it was disclosed. The Shadowserver Foundation counted 274 compromised Zimbra servers in a single recent week.

Cisco has confirmed that attackers are actively exploiting a critical vulnerability in the software many businesses use to connect their offices together. The flaw, tracked as CVE-2026-76504 and rated 9.8 out of 10 on the CVSS severity scale, affects Cisco Catalyst SD-WAN Manager. It lets a remote attacker slip past a login check and gain administrator-level access to a protected management API. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has already added it to its Known Exploited Vulnerabilities (KEV) catalog and gave federal agencies until October 3, 2026 to fix it.