CVE-2025-20333

CRITICALCVSS 9.9Known Exploited

CISA Known Exploited Vulnerability

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

Remediation deadline: September 26, 2025

Description

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.

Timeline

Published:September 25th, 2025 4:15 PM

Last modified:October 18th, 2026 9:10 PM

Added to KEV:September 25th, 2025

CVSS Scoring

CVSS v3: 9.9 (CRITICAL)

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

Affected Software

From NVD CPE configuration data

Vendors

cisco

Products

adaptive_security_appliance_softwaresecure_firewall_threat_defense

Weaknesses (CWE)

CWE-120

References & Reports

Advisories, patches, and third-party reports

Source: NIST NVD · Data may lag official sources by up to one minute