Cisco has patched a critical vulnerability in Cisco Secure Email Gateway affecting the Advanced Malware Protection (AMP) feature. The flaw lies in how AMP processes email attachments when the file reputation service is enabled. An unauthenticated remote attacker can exploit this to write arbitrary files to the underlying operating system. Successful exploitation can lead to command execution with root privileges, severely impacting system integrity. Cisco has confirmed active exploitation in the wild and has shared Indicators of Compromise and background information. No public Proof-of-Concept or exploit code is currently known, but NCSC considers it likely that one will emerge shortly. NCSC anticipates increased scanning traffic and exploitation attempts as a result.