CVE-2025-20333
CriticalExploitedPublic exploitA 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.
Published Sep 25, 2025 · Updated Aug 11, 2026
Key Facts
Patch immediately- CVE-2025-20333 is a critical-severity vulnerability (CVSS 9.9 v3.1) affecting Firepower Threat Defense (Cisco), Secure Firewall Threat Defense (Cisco), Adaptive Security Appliance Software (Cisco) and 2 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 25, 2025. Public exploit code is available.
- EPSS estimates a 71% probability of exploitation in the next 30 days.
- Fixed versions are available, including Adaptive Security Appliance Software 9.12.4.72, Adaptive Security Appliance Software 9.14.4.28, Adaptive Security Appliance Software 9.16.4.85.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
9.9
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
71%
Higher than 99.4% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2025-20333 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Sep 25, 2025 | Sep 26, 2025 | Not reported |
| Industry KEV feed | Sep 25, 2025 | Sep 26, 2025 | Not reported |
| CIRCL KEV | Sep 25, 2025 | Sep 26, 2025 | Not reported |
| ENISA EUVD | Sep 25, 2025 | n/a | Not reported |
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.
Affected Products
7 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Firepower Threat DefenseCisco | 7.6.0 | 7.0.8.1 |
| Secure Firewall Threat DefenseCisco | 7.6.0 | 7.0.8.1 |
| Adaptive Security Appliance SoftwareCisco | See advisory | 9.12.4.72 |
| Cisco Secure Firewall Adaptive Security Appliance (ASA) Software | >= 9.8.1 | n/a |
| Cisco Secure Firewall Threat Defense (FTD) Software | >= 6.2.3 | n/a |
Patched Releases
Adaptive Security Appliance Software
9.12.4.72, 9.14.4.28, 9.16.4.85, 9.17.1.45, 9.18.4.47, 9.19.1.37, 9.20.3.7, 9.22.1.3
Firepower Threat Defense
7.0.8.1
Secure Firewall Threat Defense
7.0.8.1, 7.2.9, 7.4.2.4
Timeline
Publicly disclosed
Sep 25, 2025
Added to CISA KEV
Sep 25, 2025
Added to Industry KEV feed
Sep 25, 2025
Added to CIRCL KEV
Sep 25, 2025
Added to ENISA EUVD
Sep 25, 2025
Last updated
Aug 11, 2026
Weakness Type
- CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
References
- advisorycisco-sa-asaftd-webvpn-z5xP8EUB
- advisoryVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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.
Affected: Firepower Threat Defense (Cisco) versions 7.6.0; Secure Firewall Threat Defense (Cisco) versions 7.6.0; Adaptive Security Appliance Software (Cisco), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Sep 25, 2025.
Yes. It was added on Sep 25, 2025 with a federal remediation due date of Sep 26, 2025.
Public exploit code is available.
Fixed versions are available, including Adaptive Security Appliance Software 9.12.4.72, Adaptive Security Appliance Software 9.14.4.28, Adaptive Security Appliance Software 9.16.4.85.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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