CVE-2025-20333

CRITICAL severity · CVSS 9.9 · Buffer overflow · actively exploited (CISA KEV)

9.9CVSS CRITICAL ● exploited

🔴 Actively exploited in the wild (CISA Known Exploited Vulnerabilities). Added to KEV 2025-09-25. US federal agencies must patch by 2025-09-26.

Summary

A vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an authenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP(S) requests. An attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. A successful exploit could allow the attacker to execute arbitrary code as root, possibly resulting in the complete compromise of the affected device.

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredLow

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)27%

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products we track (1)

Cisco ASA

Recommendation

This vulnerability is being actively exploited in the wild — patch affected products urgently. Open any affected product above for its exact safe version.

CVE-2025-20333

Summary

Impact & exploitability

Affected products we track (1)

Recommendation

Additional information