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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 26 Sep 2025.
Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2025-20333

CRITICAL · 9.9 CVSS v3.1 Published 2025-09-25
Fix available
A fix is available. Upgrade to 7.0.8.1 / 7.2.9 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Improper validation of user-supplied input in HTTP(S) requests to the VPN web server of Cisco ASA and FTD allows an authenticated attacker with valid VPN credentials to send crafted requests and execute arbitrary code as root, achieving full device compromise.

MitigationApply the vendor-supplied patch/update for CVE-2025-20333 to affected ASA/FTD versions; restrict VPN access to essential personnel until patched.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Adaptive Security Appliance SoftwareOperating system
Affected:>= 9.12, < 9.12.4.72>= 9.14, < 9.14.4.28>= 9.16, < 9.16.4.85>= 9.17.0, < 9.17.1.45>= 9.18, < 9.18.4.47>= 9.19, < 9.19.1.37>= 9.20, < 9.20.3.7>= 9.22, < 9.22.1.3
Secure Firewall Threat DefenseApplication
Affected:>= 7.0.0, < 7.0.8.1>= 7.1.0, < 7.2.9>= 7.3.0, < 7.4.2.4= 7.6.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify device type and software platform
    Run 'show version' on the device CLI. Look for 'Cisco Adaptive Security Appliance Software' or 'Cisco Firepower Threat Defense' in the output to determine if it is ASA or FTD.
    Affected if Device runs ASA or FTD software.
  2. Check ASA software version
    If the device is ASA, run 'show version | include Version' to get the exact version number. Compare against the affected ranges: 9.12.x < 9.12.4.72, 9.14.x < 9.14.4.28, 9.16.x < 9.16.4.85, 9.17.x < 9.17.1.45, 9.18.x < 9.18.4.47, 9.19.x < 9.19.1.37, 9.20.x < 9.20.3.7, or 9.22.x < 9.22.1.3.
    Affected if The ASA version falls within any of the listed vulnerable ranges.
  3. Check FTD software version
    If the device is FTD, run 'show version' to get the exact version number. Compare against the affected ranges: 7.0.x < 7.0.8.1, 7.1.x < 7.2.9, 7.3.x < 7.4.2.4, or 7.6.0 exactly.
    Affected if The FTD version falls within any of the listed vulnerable ranges.
  4. Verify VPN web server is accessible
    Confirm that the device has VPN functionality enabled and the VPN web server (HTTP/HTTPS for VPN portal) is accessible from the network. This is typically enabled by default when AnyConnect or client VPN is configured. Use 'show run webvpn' or check the VPN configuration.
    Affected if VPN web server is accessible and the device runs a vulnerable ASA or FTD version.

The environment is affected if the device runs Cisco ASA or FTD software in any of the specified vulnerable version ranges AND has VPN web server access enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.0.8.1 / 7.2.9 / 7.4.2.4 or later
Fixed in 7.0.8.17.2.97.4.2.4
Interim mitigation

Apply the vendor-supplied patch/update for CVE-2025-20333 to affected ASA/FTD versions; restrict VPN access to essential personnel until patched.

Recommended fix High confidence

Upgrade to ASA 9.12.4.72 / 9.14.4.28 / 9.16.4.85 / 9.17.1.45 or FTD 7.0.8.1 / 7.2.9 / 7.4.2.4 (or subsequent patches) - select based on current branch

  1. 1. Identify the exact ASA or FTD version currently running using 'show version' command
  2. 2. Determine which software branch (ASA 9.12, 9.14, 9.16, 9.17 or FTD 7.0, 7.1, 7.3, 7.6) is in use
  3. 3. For ASA: Upgrade to the minimum fixed version for your branch: 9.12.4.72, 9.14.4.28, 9.16.4.85, or 9.17.1.45
  4. 4. For FTD: Upgrade to the minimum fixed version for your branch: 7.0.8.1, 7.2.9, 7.4.2.4, or the 7.6.1 patch (if available)
  5. 5. Download the appropriate Cisco ASA or FTD software image from the Cisco Software Download Center (requires valid CCO account)
  6. 6. Upload the new image to the device using 'copy' command or through the management interface
  7. 7. Reload the device using 'reload' command to apply the new image
  8. 8. After reload, verify the new version is installed with 'show version'
Caveat Review Cisco release notes for upgrade path prerequisites; some branches may require intermediate upgrades. FTD upgrades may require FMC compatibility checks.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Adaptive Security Appliance Software Exploited in the wild — priority engagement
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-20333 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data