Cisco Warns of Active Attacks Exploiting Unpatched 0-Day in AsyncOS Email Security Appliances

🗓️ 18 Dec 2025 04:10:00Reported by The Hacker NewsType

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Cisco reports active zero-day in AsyncOS email appliances exploited via internet-exposed Spam Quarantine.

Reporter	Title	Published	Views	Family All 30
GithubExploit	Exploit for CVE-2025-20393	18 Dec 202512:10	–	githubexploit
GithubExploit	Exploit for CVE-2025-20393	18 Dec 202507:25	–	githubexploit
ATTACKERKB	CVE-2025-20393	17 Dec 202516:47	–	attackerkb
BDU FSTEC	The vulnerability of the Spam Quarantine function in the Cisco AsyncOS operating system, within the tools of Cisco Secure Email and Web Manager, as well as Cisco Secure Email Gateway, allows a malicious user to execute arbitrary code with root privileges.	19 Dec 202500:00	–	bdu_fstec
Circl	CVE-2025-20393	17 Dec 202517:03	–	circl
CISA KEV Catalog	Cisco Multiple Products Improper Input Validation Vulnerability	17 Dec 202500:00	–	cisa_kev
CISA	CISA Adds Three Known Exploited Vulnerabilities to Catalog	17 Dec 202512:00	–	cisa
Cisco	Reports About Cyberattacks Against Cisco Secure Email Gateway And Cisco Secure Email and Web Manager	17 Dec 202516:00	–	cisco
Tenable Nessus	Cisco Secure Email and Web Manager RCE (cisco-sa-sma-attack-N9bf4)	25 Feb 202600:00	–	nessus
Tenable Nessus	Cisco Secure Email Gateway RCE (cisco-sa-sma-attack-N9bf4)	16 Jan 202600:00	–	nessus

20 Dec 2025 12:11Current

7.1High risk

Vulners AI Score7.1

CVSS 3.110

EPSS0.29875

SSVC

zero day asyncos software email gateway spam quarantine internet exposure advanced persistent threat china nexus