Cisco patches new Secure Email Gateway zero-day exploited in attacks

A critical path traversal vulnerability in Cisco's Secure Email Gateway allowed unauthenticated remote attackers to execute arbitrary commands with root privileges simply by sending a malicious email attachment — the very type of threat the product is designed to stop. The flaw resided in the Advanced Malware Protection feature, meaning a security control itself became the attack surface. Active exploitation was confirmed before many organizations could apply mitigations, highlighting the danger of zero-day vulnerabilities in perimeter security appliances. This incident underscores that security infrastructure is not immune to vulnerabilities and must be subject to the same rigorous patch and monitoring discipline as any other system. Delayed patching of internet-facing appliances — especially those processing untrusted external content — can have catastrophic consequences.