18 Apr, 2026

Cisco warns of unpatched AsyncOS zero-day exploited in attacks

Cisco warned customers today of an unpatched, maximum-severity Cisco AsyncOS zero-day actively exploited in attacks targeting Secure Email Gateway (SEG) and Secure Email and Web Manager (SEWM) appliances. This yet-to-be-patched zero-day (CVE-2025-20393) affects only Cisco SEG and Cisco SEWM appliances with non-standard configurations, when the Spam Quarantine feature is enabled and exposed on the Internet. […]

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