CVE-2025-20393 Cisco Multiple Products Improper Input Validation
Unauthenticated remote attackers can execute arbitrary system commands with root privileges via crafted HTTP requests to the Spam Quarantine feature.
- Exploited in the wild
- Since 17 Dec 2025
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-20393?
CVE-2025-20393 is a critical command injection vulnerability in Cisco Asyncos, published on 17 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-20
Which versions are affected by CVE-2025-20393?
It affects 1 product.
Products include Cisco Asyncos.
How do I fix CVE-2025-20393?
No fix has been published for CVE-2025-20393 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 24 Dec 2025.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2025-20393 being exploited?
Yes. Attackers have exploited CVE-2025-20393 in the wild since at least 17 Dec 2025.
Public exploit code: 4 proofs of concept on GitHub.
Other vulnerabilities in Cisco Asyncos
- CVE-2026-76519 Cisco Secure Email Gateway Relative Path Traversal
- CVE-2026-76461 Cisco Secure Email Gateway SQL Injection
- CVE-2024-20435 Command injection in Cisco Secure Web Appliance
- CVE-2019-15956 Cisco Web Security Appliance Unauthorized Device Reset Vulnerability
- CVE-2021-34698 Cisco Web Security Appliance Proxy Service Denial of Service Vulnerability
Sources
Also known as GHSA-mrgj-cg36-fgq8.