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9.9
CRITICAL CVSS 3.1
CVE-2025-20333
"Cisco Secure Firewall Arbitrary Code Execution 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.

INFO

Published Date :

Sept. 25, 2025, 4:15 p.m.

Last Modified :

Sept. 25, 2025, 6:15 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2025-20333 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco adaptive_security_appliance_software
2 Cisco firepower_threat_defense
: Total Affected Vendor : 1 | Products : 2
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL [email protected]
Solution
Apply vendor patches to fix improper input validation and prevent code execution.
  • Update Cisco Secure Firewall ASA Software.
  • Update Cisco Secure Firewall FTD Software.
  • Apply vendor-provided security patches.
  • Restrict access to VPN web server.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-20333.

URL Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-z5xP8EUB
https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-20333 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-20333 weaknesses.

CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-42: MIME Conversion MIME Conversion CAPEC-44: Overflow Binary Resource File Overflow Binary Resource File CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-92: Forced Integer Overflow Forced Integer Overflow CAPEC-100: Overflow Buffers Overflow Buffers

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-20333 vulnerability anywhere in the article.

  • The Hacker News
Urgent: Cisco ASA Zero-Day Duo Under Attack; CISA Triggers Emergency Mitigation Directive

Sep 25, 2025Ravie LakshmananZero-Day / Vulnerability Cisco is urging customers to patch two security flaws impacting the VPN web server of Cisco Secure Firewall Adaptive Security Appliance (ASA) Sof ... Read more

Published Date: Sep 25, 2025 (3 hours, 8 minutes ago)
  • BleepingComputer
CISA orders agencies to patch Cisco flaws exploited in zero-day attacks

CISA has issued a new emergency directive ordering U.S. federal agencies to secure their Cisco firewall devices against two flaws that have been exploited in zero-day attacks. Emergency Directive 25-0 ... Read more

Published Date: Sep 25, 2025 (3 hours, 32 minutes ago)
  • BleepingComputer
Cisco warns of ASA firewall zero-days exploited in attacks

Cisco warned customers today to patch two zero-day vulnerabilities that are actively being exploited in attacks and impact the company's firewall software. The first one (CVE-2025-20333) allows authen ... Read more

Published Date: Sep 25, 2025 (4 hours, 36 minutes ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-20333 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Sep. 25, 2025

    Action Type Old Value New Value
    Added Reference https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks
  • New CVE Received by [email protected]

    Sep. 25, 2025

    Action Type Old Value New Value
    Added 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.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    Added CWE CWE-120
    Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-z5xP8EUB
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 9.9
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact