CVE-2025-20333

CRITICAL KEV

Cisco Secure Firewall ASA/FTD - RCE

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2025-20333 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added September 25, 2025. EIP tracks 1 public exploit from researchers including curtishoughton.

AI-analyzed exploit summary This repository contains a Python-based scanner that checks for the presence of vulnerable endpoints related to CVE-2025-20333, a heap buffer overflow vulnerability in Cisco ASA/FTD WebVPN file upload handler. The scanner performs safe GET requests to detect reachable endpoints but does not attempt exploitation.

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.

Exploits (1)

nomisec SCANNER
by curtishoughton · poc
https://github.com/curtishoughton/Cisco-ASA-CVE-2025-20333-Scanner

This repository contains a Python-based scanner that checks for the presence of vulnerable endpoints related to CVE-2025-20333, a heap buffer overflow vulnerability in Cisco ASA/FTD WebVPN file upload handler. The scanner performs safe GET requests to detect reachable endpoints but does not attempt exploitation.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Cisco Secure ASA and Cisco Secure FTD with WebVPN / AnyConnect enabled
Auth required
Prerequisites: WebVPN/AnyConnect enabled · Access to vulnerable endpoints
devstral-2 · analyzed May 17, 2026 Full analysis →

Scores

CVSS v3 9.9
EPSS 0.2465
EPSS Percentile 96.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation active
Automatable no
Technical Impact total

Details

CISA KEV 2025-09-25
VulnCheck KEV 2025-09-25
ENISA EUVD EUVD-2025-31140
CWE
CWE-120
Status published
Products (3)
cisco/adaptive_security_appliance_software 9.12 - 9.12.4.72
cisco/firepower_threat_defense 7.6.0
cisco/firepower_threat_defense 7.0.0 - 7.0.8.1
Published Sep 25, 2025
KEV Added Sep 25, 2025
Tracked Since Feb 18, 2026