CVE-2025-20393

Published Dec 17, 2025

Last updated 23 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: A vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to execute arbitrary system commands on an affected device with root privileges. This vulnerability is due to insufficient validation of HTTP requests by the Spam Quarantine feature. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.
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 is a measure of social media activity compared against trending CVEs from the past 12 months. Max score 100.

Hype score: 8

Configurations

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References

Sources include official advisories and independent security research.