What is CVE-2025-20393?

CVE-2025-20393 is a critical-severity vulnerability in Cisco Secure Email, classified under Improper Input Validation. CVSS score: 10.0/10. Published 2025-12-17.

How severe is CVE-2025-20393?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Is CVE-2025-20393 known to be exploited?

Yes. CVE-2025-20393 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-12-17), indicating it is being actively exploited. 5 public proof-of-concept repositories are indexed.

Improper input validation in Cisco Secure Email

CVE-2025-20393

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 affec…

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.065 (91.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Cisco Secure Email — versions 14.0.0-698, 13.5.1-277, 13.0.0-392
Cisco Secure Email And Web Manager — versions 13.6.2-023, 13.6.2-078, 13.0.0-249

Weakness classification (CWE)

CWE-20 — Improper Input Validation

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-12-17. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2025-12-24.

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.

Public proof-of-concept exploits

References

cisco-sa-sma-attack-N9bf4

Frequently asked questions

What is CVE-2025-20393?: CVE-2025-20393 is a critical-severity vulnerability in Cisco Secure Email, classified under Improper Input Validation. CVSS score: 10.0/10. Published 2025-12-17.
How severe is CVE-2025-20393?: Critical severity. CVSS v3 base score is 10.0 out of 10.
Is CVE-2025-20393 known to be exploited?: Yes. CVE-2025-20393 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-12-17), indicating it is being actively exploited. 5 public proof-of-concept repositories are indexed.