CVE-2025-20393 | Cisco Secure Email Gateway and Cisco Secure Email and Web Manager Remote Command Execution Vulnerability

Exp

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.

Published: 2025-12-17 Last update: 2026-01-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-20393 is rated Critical Active Threat (98.3/100): CVSS Critical severity, with high exploitation likelihood (EPSS 6.48%, 91th percentile). CISA KEV confirms active exploitation (added 2025-12-17) affecting Cisco / Multiple Products. a weakness (CWE-20) Unauthenticated remote administrative access may be possible. EPSS rose +1.35% over the last day, indicating growing attacker interest. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2025-20393

Name: Cisco Multiple Products Improper Input Validation Vulnerability · CISA KEV detail

Exploit added: 2025-12-17

Action due: 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.

Exploit prediction scoring system (EPSS) score for CVE-2025-20393

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-22 5.13% 6.48% +1.35%
2 2026-05-18 5.67% 5.13% -0.55%
3 2026-05-16 — 5.67% —

Full EPSS history (34 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-20393

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
10.0 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 6.0 [email protected]

Weakness enumeration for CVE-2025-20393

Affected software / configurations for CVE-2025-20393

Vendor Product Version Raw CPE
cisco asyncos < 15.0.5-016 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
cisco asyncos >= 15.5, < 15.5.4-012 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
cisco asyncos >= 16.0, < 16.0.4-016 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
cisco asyncos < 15.0.2-007 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
cisco asyncos >= 15.5, < 15.5.4-007 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
cisco asyncos >= 16.0, < 16.0.4-010 cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*

References for CVE-2025-20393

cvelogic Threat Intelligence