Cisco Patches AsyncOS Zero-Day Targeting SEG/SEWM Appliances
🔒 Cisco has released a fix for a maximum‑severity AsyncOS zero‑day (CVE-2025-20393) that has been exploited since November 2025. The flaw impacts Cisco Secure Email Gateway and Secure Email and Web Manager appliances with non-standard configurations when the Spam Quarantine feature is exposed to the internet, permitting arbitrary command execution as root. Cisco Talos links the intrusions to a Chinese-nexus actor tracked as UAT-9686, which deployed persistence and tunneling implants and a log-wiping utility. CISA has added the vulnerability to its known exploited vulnerabilities catalog and ordered federal remediation under BOD 22-01.
