Cisco Multiple Products Improper Input Validation Vulnerability (CVE-2025-20393)
Severity: critical · Patch status: unknown · Since 2025-12-17 · CVE-2025-20393
Cisco Secure Email Gateway, Secure Email, AsyncOS Software, and Web Manager appliances contains an improper input validation vulnerability that allows threat actors to execute arbitrary commands with root privileges on the underlying operating system of an affected appliance. CISA added CVE-2025-20393 to its Known Exploited Vulnerabilities catalog on Dec 17, 2025, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Dec 24, 2025 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch
