Email Filtering Bypass in Cisco Secure Email Gateway

CVE-2025-20153

Summary

A vulnerability exists in the email filtering mechanism of Cisco Secure Email Gateway, enabling an unauthenticated remote attacker to bypass established email rules. This issue arises from improper processing of emails that transit through the device. An attacker could exploit this flaw by sending a specially crafted email, allowing unauthorized messages that should be blocked to pass through the system. This situation poses significant risks to email security and could lead to further exploitation.

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