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Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2026-20016

MEDIUM · 6.7 CVSS v3.1 Published 2026-03-04
Fix available
A fix is available. Upgrade to 7.0.9 / 7.2.11 or later.
See remediation →
69/100
Remediation priority · Elevated
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 Cisco FXOS Software CLI feature for Cisco Secure Firewall ASA Software and Secure FTD Software could allow an authenticated, local attacker to execute arbitrary commands on the underlying operating system with root-level privileges. To exploit this vulnerability, the attacker must have valid administrative credentials on an affected device. This vulnerability is due to insufficient input validation of user-supplied command arguments. An attacker could exploit this vulnerability by submitting crafted input for specific CLI commands. A successful exploit could allow the attacker to execute commands on the underlying operating system with root-level privileges.

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

This is a command injection vulnerability in the Cisco FXOS Software CLI where an authenticated attacker with administrative credentials can execute arbitrary commands on the underlying operating system with root privileges due to insufficient input validation of user-supplied command arguments.

MitigationApply the Cisco patch/upgrade for FXOS Software when available. Until then, limit administrative access to trusted personnel and monitor for suspicious CLI activity.

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:>= 9.12.1, < 9.16.4.85>= 9.17.1, < 9.18.4.66>= 9.19.1, < 9.20.4>= 9.22.1.1, < 9.22.2.4>= 9.23.1, < 9.23.1.7
Secure Firewall Threat DefenseApplication
Affected:>= 6.4.0, < 7.0.9>= 7.1.0, < 7.2.11>= 7.3.0, < 7.4.3>= 7.6.0, < 7.6.4>= 7.7.0, < 7.7.11

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
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/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 the product type
    Run 'show version' in the CLI to determine if the device runs Cisco ASA Software or Cisco Firepower Threat Defense Software
    Affected if The device is running Cisco ASA Software or Cisco Firepower Threat Defense Software
  2. Check ASA version against affected ranges
    Run 'show version' and locate the 'Cisco Adaptive Security Appliance Software' version number. Compare it to the affected ranges: >= 9.12.1 and < 9.16.4.85; >= 9.17.1 and < 9.18.4.66; >= 9.19.1 and < 9.20.4; >= 9.22.1.1 and < 9.22.2.4; >= 9.23.1 and < 9.23.1.7
    Affected if The ASA version falls within any of these ranges
  3. Check FTD version against affected ranges
    Run 'show version' and locate the 'Cisco Firepower Threat Defense Software' version number. Compare it to the affected ranges: >= 6.4.0 and < 7.0.9; >= 7.1.0 and < 7.2.11; >= 7.3.0 and < 7.4.3; >= 7.6.0 and < 7.6.4; >= 7.7.0 and < 7.7.11
    Affected if The FTD version falls within any of these ranges
  4. Verify administrative CLI access is enabled
    Run 'show running-config | include http server' or 'show ssh' to check if remote CLI access (SSH, Telnet) is enabled. Run 'show privilege' to confirm user privilege levels.
    Affected if Remote administrative CLI access (SSH/Telnet) is enabled and user accounts with administrative privileges exist on the device

The environment is affected if the device runs ASA or FTD software with a version number matching any of the specified vulnerable ranges AND administrative CLI access is accessible to attackers.

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 7.0.9 / 7.2.11 / 7.4.3 or later
Fixed in 7.0.97.2.117.4.3
Interim mitigation

Apply the Cisco patch/upgrade for FXOS Software when available. Until then, limit administrative access to trusted personnel and monitor for suspicious CLI activity.

Recommended fix High confidence

ASA: 9.16.4.85, 9.18.4.66, 9.20.4, or 9.22.2.4 (depending on current train) | FTD: 7.0.9, 7.2.11, 7.4.3, or 7.6.4 (depending on current train)

  1. 1. Identify the currently installed Cisco ASA or FTD software version using 'show version' command
  2. 2. Determine which software train (ASA or FTD) and version line your device is running
  3. 3. For ASA Software: If running 9.12.x-9.16.x, upgrade to 9.16.4.85 or later; if 9.17.x-9.18.x, upgrade to 9.18.4.66 or later; if 9.19.x-9.20.x, upgrade to 9.20.4 or later; if 9.22.x, upgrade to 9.22.2.4 or later
  4. 4. For FTD Software: If running 6.4.x-7.0.x, upgrade to 7.0.9 or later; if 7.1.x-7.2.x, upgrade to 7.2.11 or later; if 7.3.x-7.4.x, upgrade to 7.4.3 or later; if 7.6.x, upgrade to 7.6.4 or later
  5. 5. Download the appropriate fixed software image from Cisco.com (requires valid service contract)
  6. 6. Upload the new image to the device using 'copy' command or through the device manager
  7. 7. Reload the device with the new image using 'reload' command
  8. 8. Verify the upgrade was successful and the version matches the expected fixed release using 'show version'
Caveat Major software upgrades may introduce compatibility changes with existing configurations or managed devices; review Cisco release notes for the target version before upgrading

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

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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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-2026-20016 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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