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FxosOperating system · Cisco

CVE-2018-0300

HIGH · 7.2 CVSS v3.0 Published 2018-06-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
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 process of uploading new application images to Cisco FXOS on the Cisco Firepower 4100 Series Next-Generation Firewall (NGFW) and Firepower 9300 Security Appliance could allow an authenticated, remote attacker using path traversal techniques to create or overwrite arbitrary files on an affected device. The vulnerability is due to insufficient validation during the application image upload process. An attacker could exploit this vulnerability by creating an application image containing malicious code and installing the image on the affected device using the CLI or web-based user interface (web UI). These actions occur prior to signature verification and could allow the attacker to create and execute arbitrary code with root privileges. Note: A missing or invalid signature in the application image will cause the upload process to fail, but does not prevent the exploit. Cisco Bug IDs: CSCvc21901.

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

A path traversal vulnerability in Cisco FXOS allows authenticated remote attackers to overwrite arbitrary files during the application image upload process on Firepower 4100 Series NGFW and Firepower 9300 appliances. Insufficient validation of file paths in uploaded images enables attackers to create malicious files with root privileges prior to signature verification.

MitigationApply the vendor patch from Cisco (refer to CSCvc21901) and restrict administrative access to trusted personnel only until the update is applied.

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
FxosOperating system
Affected:= 2.0\(1.68\)

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
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/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 device model
    Run 'show version' or check the physical device to confirm it is a Firepower 4100 Series NGFW or Firepower 9300 appliance
    Affected if The device is a Firepower 4100 Series or Firepower 9300
  2. Check FXOS version
    Execute 'show version' from the FXOS CLI and locate the 'Cisco FXOS' version line
    Affected if The version displayed is exactly 2.0(1.68)
  3. Verify administrative access is enabled
    From FXOS CLI, run 'show running-config' and check for any administrative user accounts or AAA configuration that permits remote authentication
    Affected if Administrative accounts exist and remote authentication (HTTP/HTTPS/SSH) is configured and enabled
  4. Confirm image upload feature accessibility
    Check if the application image upload functionality is accessible via the FXOS CLI 'scope firmware' or through the management interface
    Affected if The image upload feature is available to authenticated administrators

The environment is affected if running Cisco FXOS version 2.0(1.68) on Firepower 4100 or Firepower 9300 with administrative access enabled, allowing authenticated users to upload application images.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor patch from Cisco (refer to CSCvc21901) and restrict administrative access to trusted personnel only until the update is applied.

Fix this in Fxos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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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-2018-0300 in production — separate from our analysis above.

No notes yet

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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
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