CVE-2025-20393
Actively exploited. CVE-2025-20393 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-12-17) — exploitation has been observed in the wild, and US federal agencies are required to remediate it under BOD 22-01. Treat patching as urgent.
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2025-20393 is indexed in GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation.
On December 17, 2025, Cisco released a security advisory for a critical vulnerability affecting Cisco Secure Email Gateway and Cisco Secure Email and Web Manager products. It is recommended to follow Cisco's recommendations to check whether vulnerable appliances have been compromised, and to remediate the issue. There is no patch available for this vulnerability yet.
CSIRTS triage
- What
- A critical vulnerability could allow remote code execution on affected products.
- Who is affected
- Customers using Cisco Secure Email Gateway and Secure Email and Web Manager are affected.
- Urgency
- Remediation is critical as the vulnerability is actively exploited and no patch is available yet.
- Action
- Check for compromised appliances and follow Cisco's recommendations.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Exploitation confirmedAlready exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 98% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2025-20393 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (2)
- critical2025-042: Critical Vulnerability in Cisco Secure Email and Web Managercert-eu · 2025-12-18
- criticalexploitedCVE-2025-20393: Cisco Multiple Products Improper Input Validation Vulnerabilitycisa-kev · 2025-12-17
External references
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