Cisco warns customers of actively exploited zero-day in email gateways

Attackers are actively exploiting a critical zero-day (CVE-2026-76461) in Cisco Secure Email Gateway allowing unauthenticated remote root command execution. Cisco confirmed observed exploitation, released mitigations and IOCs, and CISA added the flaw to its Known Exploited Vulnerabilities catalog; customers are urged to patch and hunt for signs of compromise immediately.