CVE-2025-20393
CriticalExploitedPublic exploitA 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.
Published Dec 18, 2025 · Updated Oct 7, 2026 · Also known as TR-25-0465
Key Facts
Patch immediately- CVE-2025-20393 is a critical-severity vulnerability (CVSS 10.0 v3.1) affecting Asyncos (Cisco), Cisco Secure Email, Cisco Secure Email and Web Manager.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Dec 17, 2025. Public exploit code is available.
- EPSS estimates a 32% probability of exploitation in the next 30 days.
- Fixed versions are available, including Asyncos 15.0.5-016.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
10.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
32%
Higher than 98.3% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
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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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Dec 17, 2025 | Dec 24, 2025 | Not reported |
| Industry KEV feed | Dec 17, 2025 | Dec 24, 2025 | Not reported |
| CIRCL KEV | Dec 17, 2025 | Dec 24, 2025 | Not reported |
| ENISA EUVD | Dec 17, 2025 | n/a | Not reported |
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.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| AsyncosCisco | See advisory | 15.0.5-016 |
| Cisco Secure Email | >= 14.0.0-698 | n/a |
| Cisco Secure Email and Web Manager | >= 13.6.2-023 | n/a |
Patched Releases
Asyncos
15.0.5-016
Timeline
Added to CISA KEV
Dec 17, 2025
Added to Industry KEV feed
Dec 17, 2025
Added to CIRCL KEV
Dec 17, 2025
Added to ENISA EUVD
Dec 17, 2025
Publicly disclosed
Dec 18, 2025
Last updated
Oct 7, 2026
Weakness Type
- CWE-20 Improper Input Validation
References
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2025-20393
- advisorycisco-sa-sma-attack-N9bf4
- advisoryUSOM advisory
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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.
Affected: Asyncos (Cisco); Cisco Secure Email versions >= 14.0.0-698; Cisco Secure Email and Web Manager versions >= 13.6.2-023. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Dec 17, 2025.
Yes. It was added on Dec 17, 2025 with a federal remediation due date of Dec 24, 2025.
Public exploit code is available.
Fixed versions are available, including Asyncos 15.0.5-016.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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