Root RCE Zero-Day in Cisco Secure Email Gateway Under Active Exploitation

Cisco has disclosed that a critical zero-day vulnerability, tracked as CVE-2026-76461, is currently being actively exploited against its Secure Email Gateway appliances. With a CVSS score of 9.8, this flaw in the AsyncOS software enables unauthenticated attackers to achieve root-level access and execute arbitrary commands by sending specially crafted emails containing malicious SQL statements. The Cybersecurity and Infrastructure Security Agency (CISA) has added the vulnerability to its Known Exploited Vulnerabilities catalog, urging federal agencies to remediate the issue urgently. While specific threat actors have not been identified, the exploitation highlights severe risks for both physical and virtual instances of the Secure Email Gateway.