CVE-2025-20393

Name: CVE-2025-20393
Creator: NVD / NIST
Published: 2025-12-17T17:15:48.523+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 10/10Actively ExploitedEPSS 29.06%

Last modified Jun 17, 2026

CVE-2025-20393 is a critical-severity vulnerability rated 10/10 on the CVSS scale. 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. CISA has confirmed active exploitation in the wild. EPSS estimates a 29.06% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

10/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

EPSS Probability

29.06%

97.9th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Dec 24, 2025.

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Cisco	Asyncos	< 15.0.5-016
Cisco	Asyncos	>= 15.5, < 15.5.4-012
Cisco	Asyncos	>= 16.0, < 16.0.4-016
Cisco	Asyncos	< 15.0.2-007
Cisco	Asyncos	>= 15.5, < 15.5.4-007
Cisco	Asyncos	>= 16.0, < 16.0.4-010

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20393US Government Resource

Timeline

Published: Dec 17, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-20393?

How severe is CVE-2025-20393?

CVE-2025-20393 has a CVSS score of 10/10 (CRITICAL severity). The EPSS model estimates a 29.06% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2025-20393?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-20393?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST