CVE-2025-20393
Cisco Multiple Products Improper Input Validation Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 24 December 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
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.
- CVSS 3.1
- 10.0 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 32.39% probability · 98th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 17 December 2025 · due 24 December 2025
- Weakness
- CWE-20
- Affected
- cisco/asyncos
- Source
- psirt@cisco.com
EPSS moved from 32.4% on 24 September 2026 to 32.4% on 30 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Please adhere to Cisco's guidelines to assess exposure and mitigate risks. Check for signs of potential compromise on all internet accessible Cisco products affected by this vulnerability. Apply any final mitigations provided by the vendor as soon as they become available. For more information please see: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ; https://nvd.nist.gov/vuln/detail/CVE-2025-20393
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.