CVEvulnerability

CVE-2025-20333

9.9 CRITICAL Known exploited Published 2025-09-25 Modified 2026-10-18 Official page ↗

CISA Known Exploited Vulnerability

Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Vulnerability — Cisco Secure Firewall Adaptive Security Appliance and Secure Firewall Threat Defense

Cisco Secure Firewall Adaptive Security (ASA) Appliance and Secure Firewall Threat Defense (FTD) Software VPN Web Server contain a buffer overflow vulnerability that allows for remote code execution. This vulnerability could be chained with CVE-2025-20362.

Added to KEV
2025-09-25
Remediation due
2025-09-26
Ransomware use
Unknown
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.
Notes
CISA Mitigation Instructions: https://www.cisa.gov/news-events/directives/ed-25-03-identify-and-mitigate-potential-compromise-cisco-devices ; https://www.cisa.gov/news-events/directives/supplemental-direction-ed-25-03-core-dump-and-hunt-instructions ; https://www.cisa.gov/eviction-strategies-tool/create-from-template ; https://sec.cloudapps.cisco.com/security/center/resources/asa_ftd_continued_attacks ; https://sec.cloudapps.cisco.com/security/center/private/resources/asa_ftd_continued_attacks#Details ; https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-webvpn-z5xP8EUB ; https://nvd.nist.gov/vuln/detail/CVE-2025-20333
Status
Analyzed
Published
2025-09-25
Last modified
2026-10-18
Assigner
[email protected]
CVSS 3.1 ([email protected])
9.9 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weaknesses
CWE-120

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.

Affected configurations

• cisco adaptive security appliance software (>= 9.12 < 9.12.4.72) • cisco adaptive security appliance software (>= 9.14 < 9.14.4.28) • cisco adaptive security appliance software (>= 9.16 < 9.16.4.85) • cisco adaptive security appliance software (>= 9.17.0 < 9.17.1.45) • cisco adaptive security appliance software (>= 9.18 < 9.18.4.47) • cisco adaptive security appliance software (>= 9.19 < 9.19.1.37) • cisco adaptive security appliance software (>= 9.20 < 9.20.3.7) • cisco adaptive security appliance software (>= 9.22 < 9.22.1.3) • cisco secure firewall threat defense (>= 7.0.0 < 7.0.8.1) • cisco secure firewall threat defense (>= 7.1.0 < 7.2.9) • cisco secure firewall threat defense (>= 7.3.0 < 7.4.2.4) • cisco secure firewall threat defense 7.6.0

Related

Weakness · CWE (1)

  • CWE-120 Buffer Copy without Checking Size of Input weakness

References