CVE-2025-20333

Published Sep 25, 2025

Last updated 8 months ago

Exploit known CVSS critical 9.9

Cisco ASA

Cisco FTD

Network

VPN

Port (443)

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-20333 is a vulnerability in the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software. It stems from improper validation of user-supplied input in HTTP(S) requests. An authenticated, remote attacker with valid VPN user credentials could exploit this vulnerability by sending crafted HTTP requests to an affected device. Successful exploitation could allow the attacker to execute arbitrary code as root, potentially leading to complete compromise of the device. Cisco has released software updates to address this vulnerability.

Description: 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.
Source: psirt@cisco.com
NVD status: Analyzed
Products: adaptive_security_appliance_software, firepower_threat_defense

Risk scores

CVSS 3.1

Type: Secondary
Base score: 9.9
Impact score: 6
Exploitability score: 3.1
Vector string: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Severity: CRITICAL

Known exploits

Data from CISA

Vulnerability name: Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability
Exploit added on: Sep 25, 2025
Exploit action due: Sep 26, 2025
Required action: The KEV due date refers to the deadline by which FCEB agencies are expected to review and begin implementing the guidance outlined in Emergency Directive (ED) 25-03 (URL listed below in Notes). Agencies must follow the mitigation steps provided by CISA (URL listed below in Notes) and vendor’s instructions (URL listed below in Notes). Adhere to the applicable BOD 22-01 guidance for cloud services or discontinue use of the product if mitigations are not available.

Weaknesses

psirt@cisco.com: CWE-120

Hype score: Not currently trending

Configurations

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References

Sources include official advisories and independent security research.