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CVE-2025-20333

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

  • Critical 9.9
  • Exploited: added to CISA KEV 25 Sep 2025

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.

Key facts

Published
25 Sep 2025
Last changed
26 Feb 2026
Assigned by
cisco
KEV added
25 Sep 2025
KEV fix due
26 Sep 2025
EPSS
72.037% likely to be exploited in the next 30 days, higher than 99.439% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 9.9CVSS 3.1, Criticalfrom the CNA (cisco)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

What to do

  • 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.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
CiscoCisco Secure Firewall Adaptive Security Appliance (ASA) Software
  • 9.8.1 (affected)
  • 9.8.1.5 (affected)
  • 9.8.1.7 (affected)
  • 9.8.2 (affected)
  • 9.8.2.8 (affected)
  • 9.8.2.14 (affected)
  • 9.8.2.15 (affected)
  • 9.8.2.17 (affected)
  • 9.8.2.20 (affected)
  • 9.8.2.24 (affected)
  • 9.8.2.26 (affected)
  • 9.8.2.28 (affected)
  • 9.8.2.33 (affected)
  • 9.8.2.35 (affected)
  • 9.8.2.38 (affected)
  • 9.8.3.8 (affected)
  • 9.8.3.11 (affected)
  • 9.8.3.14 (affected)
  • 9.8.3.16 (affected)
  • 9.8.3.18 (affected)
  • 9.8.3.21 (affected)
  • 9.8.3 (affected)
  • 9.8.3.26 (affected)
  • 9.8.3.29 (affected)
  • 9.8.4 (affected)
  • 9.8.4.3 (affected)
  • 9.8.4.7 (affected)
  • 9.8.4.8 (affected)
  • 9.8.4.10 (affected)
  • 9.8.4.12 (affected)
  • 9.8.4.15 (affected)
  • 9.8.4.17 (affected)
  • 9.8.2.45 (affected)
  • 9.8.4.25 (affected)
  • 9.8.4.20 (affected)
  • 9.8.4.22 (affected)
  • 9.8.4.26 (affected)
  • 9.8.4.29 (affected)
  • 9.8.4.32 (affected)
  • 9.8.4.33 (affected)
  • 9.8.4.34 (affected)
  • 9.8.4.35 (affected)
  • 9.8.4.39 (affected)
  • 9.8.4.40 (affected)
  • 9.8.4.41 (affected)
  • 9.8.4.43 (affected)
  • 9.8.4.44 (affected)
  • 9.8.4.45 (affected)
  • 9.8.4.46 (affected)
  • 9.8.4.48 (affected)
  • 9.12.1 (affected)
  • 9.12.1.2 (affected)
  • 9.12.1.3 (affected)
  • 9.12.2 (affected)
  • 9.12.2.4 (affected)
  • 9.12.2.5 (affected)
  • 9.12.2.9 (affected)
  • 9.12.3 (affected)
  • 9.12.3.2 (affected)
  • 9.12.3.7 (affected)
  • 9.12.4 (affected)
  • 9.12.3.12 (affected)
  • 9.12.3.9 (affected)
  • 9.12.2.1 (affected)
  • 9.12.4.2 (affected)
  • 9.12.4.4 (affected)
  • 9.12.4.7 (affected)
  • 9.12.4.10 (affected)
  • 9.12.4.13 (affected)
  • 9.12.4.8 (affected)
  • 9.12.4.18 (affected)
  • 9.12.4.24 (affected)
  • 9.12.4.26 (affected)
  • 9.12.4.29 (affected)
  • 9.12.4.30 (affected)
  • 9.12.4.35 (affected)
  • 9.12.4.37 (affected)
  • 9.12.4.38 (affected)
  • 9.12.4.39 (affected)
  • 9.12.4.40 (affected)
  • 9.12.4.41 (affected)
  • 9.12.4.47 (affected)
  • 9.12.4.48 (affected)
  • 9.12.4.50 (affected)
  • 9.12.4.52 (affected)
  • 9.12.4.54 (affected)
  • 9.12.4.55 (affected)
  • 9.12.4.56 (affected)
  • 9.12.4.58 (affected)
  • 9.12.4.62 (affected)
  • 9.12.4.65 (affected)
  • 9.12.4.67 (affected)
  • 9.14.1 (affected)
  • 9.14.1.10 (affected)
  • 9.14.1.6 (affected)
  • 9.14.1.15 (affected)
  • 9.14.1.19 (affected)
  • 9.14.1.30 (affected)
  • 9.14.2 (affected)
  • 9.14.2.4 (affected)
  • 9.14.2.8 (affected)
  • 9.14.2.13 (affected)
  • 9.14.2.15 (affected)
  • 9.14.3 (affected)
  • 9.14.3.1 (affected)
  • 9.14.3.9 (affected)
  • 9.14.3.11 (affected)
  • 9.14.3.13 (affected)
  • 9.14.3.18 (affected)
  • 9.14.3.15 (affected)
  • 9.14.4 (affected)
  • 9.14.4.6 (affected)
  • 9.14.4.7 (affected)
  • 9.14.4.12 (affected)
  • 9.14.4.13 (affected)
  • 9.14.4.14 (affected)
  • 9.14.4.15 (affected)
  • 9.14.4.17 (affected)
  • 9.14.4.22 (affected)
  • 9.14.4.23 (affected)
  • 9.14.4.24 (affected)
  • 9.16.1 (affected)
  • 9.16.1.28 (affected)
  • 9.16.2 (affected)
  • 9.16.2.3 (affected)
  • 9.16.2.7 (affected)
  • 9.16.2.11 (affected)
  • 9.16.2.13 (affected)
  • 9.16.2.14 (affected)
  • 9.16.3 (affected)
  • 9.16.3.3 (affected)
  • 9.16.3.14 (affected)
  • 9.16.3.15 (affected)
  • 9.16.3.19 (affected)
  • 9.16.3.23 (affected)
  • 9.16.4 (affected)
  • 9.16.4.9 (affected)
  • 9.16.4.14 (affected)
  • 9.16.4.18 (affected)
  • 9.16.4.19 (affected)
  • 9.16.4.27 (affected)
  • 9.16.4.38 (affected)
  • 9.16.4.39 (affected)
  • 9.16.4.42 (affected)
  • 9.16.4.48 (affected)
  • 9.16.4.55 (affected)
  • 9.16.4.57 (affected)
  • 9.16.4.61 (affected)
  • 9.16.4.62 (affected)
  • 9.16.4.67 (affected)
  • 9.16.4.70 (affected)
  • 9.16.4.71 (affected)
  • 9.16.4.76 (affected)
  • 9.16.4.82 (affected)
  • 9.16.4.84 (affected)
  • 9.17.1 (affected)
  • 9.17.1.7 (affected)
  • 9.17.1.9 (affected)
  • 9.17.1.10 (affected)
  • 9.17.1.11 (affected)
  • 9.17.1.13 (affected)
  • 9.17.1.15 (affected)
  • 9.17.1.20 (affected)
  • 9.17.1.30 (affected)
  • 9.17.1.33 (affected)
  • 9.17.1.39 (affected)
  • 9.18.1 (affected)
  • 9.18.1.3 (affected)
  • 9.18.2 (affected)
  • 9.18.2.5 (affected)
  • 9.18.2.7 (affected)
  • 9.18.2.8 (affected)
  • 9.18.3 (affected)
  • 9.18.3.39 (affected)
  • 9.18.3.46 (affected)
  • 9.18.3.53 (affected)
  • 9.18.3.55 (affected)
  • 9.18.3.56 (affected)
  • 9.18.4 (affected)
  • 9.18.4.5 (affected)
  • 9.18.4.8 (affected)
  • 9.18.4.22 (affected)
  • 9.18.4.24 (affected)
  • 9.18.4.29 (affected)
  • 9.18.4.34 (affected)
  • 9.18.4.40 (affected)
  • 9.19.1 (affected)
  • 9.19.1.5 (affected)
  • 9.19.1.9 (affected)
  • 9.19.1.12 (affected)
  • 9.19.1.18 (affected)
  • 9.19.1.22 (affected)
  • 9.19.1.24 (affected)
  • 9.19.1.27 (affected)
  • 9.19.1.28 (affected)
  • 9.19.1.31 (affected)
  • 9.20.1 (affected)
  • 9.20.1.5 (affected)
  • 9.20.2 (affected)
  • 9.20.2.10 (affected)
  • 9.20.2.21 (affected)
  • 9.20.2.22 (affected)
  • 9.20.3 (affected)
  • 9.20.3.4 (affected)
  • 9.22.1.1 (affected)
  • 9.22.1.2 (affected)
CiscoCisco Secure Firewall Threat Defense (FTD) Software
  • 6.2.3 (affected)
  • 6.2.3.1 (affected)
  • 6.2.3.2 (affected)
  • 6.2.3.3 (affected)
  • 6.2.3.4 (affected)
  • 6.2.3.5 (affected)
  • 6.2.3.6 (affected)
  • 6.2.3.7 (affected)
  • 6.2.3.8 (affected)
  • 6.2.3.10 (affected)
  • 6.2.3.11 (affected)
  • 6.2.3.9 (affected)
  • 6.2.3.12 (affected)
  • 6.2.3.13 (affected)
  • 6.2.3.14 (affected)
  • 6.2.3.15 (affected)
  • 6.2.3.16 (affected)
  • 6.2.3.17 (affected)
  • 6.2.3.18 (affected)
  • 6.6.0 (affected)
  • 6.6.0.1 (affected)
  • 6.6.1 (affected)
  • 6.6.3 (affected)
  • 6.6.4 (affected)
  • 6.6.5 (affected)
  • 6.6.5.1 (affected)
  • 6.6.5.2 (affected)
  • 6.6.7 (affected)
  • 6.6.7.1 (affected)
  • 6.6.7.2 (affected)
  • 6.4.0 (affected)
  • 6.4.0.1 (affected)
  • 6.4.0.3 (affected)
  • 6.4.0.2 (affected)
  • 6.4.0.4 (affected)
  • 6.4.0.5 (affected)
  • 6.4.0.6 (affected)
  • 6.4.0.7 (affected)
  • 6.4.0.8 (affected)
  • 6.4.0.9 (affected)
  • 6.4.0.10 (affected)
  • 6.4.0.11 (affected)
  • 6.4.0.12 (affected)
  • 6.4.0.13 (affected)
  • 6.4.0.14 (affected)
  • 6.4.0.15 (affected)
  • 6.4.0.16 (affected)
  • 6.4.0.17 (affected)
  • 6.4.0.18 (affected)
  • 7.0.0 (affected)
  • 7.0.0.1 (affected)
  • 7.0.1 (affected)
  • 7.0.1.1 (affected)
  • 7.0.2 (affected)
  • 7.0.2.1 (affected)
  • 7.0.3 (affected)
  • 7.0.4 (affected)
  • 7.0.5 (affected)
  • 7.0.6 (affected)
  • 7.0.6.1 (affected)
  • 7.0.6.2 (affected)
  • 7.0.6.3 (affected)
  • 7.0.7 (affected)
  • 7.0.8 (affected)
  • 7.1.0 (affected)
  • 7.1.0.1 (affected)
  • 7.1.0.2 (affected)
  • 7.1.0.3 (affected)
  • 7.2.0 (affected)
  • 7.2.0.1 (affected)
  • 7.2.1 (affected)
  • 7.2.2 (affected)
  • 7.2.3 (affected)
  • 7.2.4 (affected)
  • 7.2.4.1 (affected)
  • 7.2.5 (affected)
  • 7.2.5.1 (affected)
  • 7.2.6 (affected)
  • 7.2.7 (affected)
  • 7.2.5.2 (affected)
  • 7.2.8 (affected)
  • 7.2.8.1 (affected)
  • 7.3.0 (affected)
  • 7.3.1 (affected)
  • 7.3.1.1 (affected)
  • 7.3.1.2 (affected)
  • 7.4.0 (affected)
  • 7.4.1 (affected)
  • 7.4.1.1 (affected)
  • 7.4.2 (affected)
  • 7.4.2.1 (affected)
  • 7.4.2.2 (affected)
  • 7.4.2.3 (affected)
  • 7.6.0 (affected)

Timeline

  1. 25 Sep 2025 CVE-2025-20333 added to CISA KEV
  2. 25 Sep 2025 Added to the CISA KEV catalogue
  3. 25 Sep 2025 Published

Weakness

References