CVE-2025-20393

Published Dec 17, 2025

Last updated 6 days ago

Cisco Secure Email Gateway

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-20393 is an improper input validation vulnerability that affects Cisco Secure Email Gateway and Cisco Secure Email and Web Manager appliances. Successful exploitation allows a remote, unauthenticated attacker to execute arbitrary commands with root privileges on the underlying operating system of the affected appliance. Specifically, the vulnerability is triggered when the Spam Quarantine feature is exposed to the internet. Attackers have been observed exploiting this vulnerability in the wild to install backdoors (like AquaShell and AquaTunnel) and tools for log manipulation (like AquaPurge) and traffic proxying (Chisel). CISA has added this vulnerability to its Known Exploited Vulnerabilities Catalog.

Description: Cisco is aware of a potential vulnerability.  Cisco is currently investigating and will update these details as appropriate as more information becomes available.
Source: psirt@cisco.com
NVD status: Analyzed
Products: asyncos

Risk scores

CVSS 3.1

Type: Secondary
Base score: 10
Impact score: 6
Exploitability score: 3.9
Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Severity: CRITICAL

Known exploits

Data from CISA

Vulnerability name: Cisco Multiple Products Improper Input Validation Vulnerability
Exploit added on: Dec 17, 2025
Exploit action due: Dec 24, 2025
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Weaknesses

psirt@cisco.com: CWE-20

Hype score: Not currently trending

Configurations

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  {
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]

References

Sources include official advisories and independent security research.