CVE-2025-20393CiscoServers and softwareDecember 17, 2025

Cisco Multiple Products Improper Input Validation Vulnerability

Critical 10Actively exploited

Description

Cisco Secure Email Gateway, Secure Email, AsyncOS Software, and Web Manager appliances contains an improper input validation vulnerability that allows threat actors to execute arbitrary commands with root privileges on the underlying operating system of an affected appliance.

What to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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Details

Vendor
Cisco
Product
Cisco AsyncOS
CVE
CVE-2025-20393
Affected versions
Cisco Secure Email 14.0: 14.0.0-698
Cisco Secure Email 13.5: 13.5.1-277; 13.5.4-038
Cisco Secure Email 13.0: 13.0.0-392; 13.0.5-007
Cisco Secure Email 14.2: 14.2.0-620; 14.2.1-020
Cisco Secure Email 14.3: 14.3.0-032
Cisco Secure Email 15.0: 15.0.0-104; 15.0.1-030; 15.0.3-002
Cisco Secure Email 15.5: 4 versions, from 15.5.0-048 to 15.5.3-022
Cisco Secure Email 16.0: 16.0.0-050; 16.0.0-054; 16.0.1-017
Cisco Secure Email and Web Manager 13.6: 13.6.1-201; 13.6.2-023; 13.6.2-078
Cisco Secure Email and Web Manager 13.0: 13.0.0-249; 13.0.0-277
Cisco Secure Email and Web Manager 13.8: 4 versions, from 13.8.1-052 to 13.8.1-108
Cisco Secure Email and Web Manager 14.0: 14.0.0-404
Cisco Secure Email and Web Manager 12.8: 12.8.1-002; 12.8.1-021
Cisco Secure Email and Web Manager 14.1: 14.1.0-227
Cisco Secure Email and Web Manager 14.2: 14.2.0-203; 14.2.0-212; 14.2.0-224
Cisco Secure Email and Web Manager 14.3: 14.3.0-120
Cisco Secure Email and Web Manager 15.0: 15.0.0-334; 15.0.1-035
Cisco Secure Email and Web Manager 15.5: 4 versions, from 15.5.1-024 to 15.5.3-017
Cisco Secure Email and Web Manager 16.0: 16.0.0-195; 16.0.1-010; 16.0.2-088 (from the advisory and NVD; check the exact builds in the official advisory)
CVSS score
10
Actively exploited
Yes, listed in the CISA Known Exploited Vulnerabilities catalog
CISA due date
December 24, 2025 (deadline for US federal agencies: a good benchmark for you too)
Source
CISA KEV – original advisory
Published
December 17, 2025

The description and the recommended action are quoted from the public advisory; severity, exploitation status and affected versions are compiled automatically from public sources and may contain errors. The vendor's original advisory prevails: check it before taking action. This information is provided without warranty and does not replace a professional assessment.

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