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Firepower Device ManagerApplication · Cisco

CVE-2021-1489

MEDIUM · 6.5 CVSS v3.1 Published 2021-04-29
Fix available
A fix is available. Upgrade to 6.4.0.12 / 6.6.4 or later.
See remediation →
71/100
Remediation priority · Elevated
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 filesystem usage management for Cisco Firepower Device Manager (FDM) Software could allow an authenticated, remote attacker to exhaust filesystem resources, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to the insufficient management of available filesystem resources. An attacker could exploit this vulnerability by uploading files to the device and exhausting available filesystem resources. A successful exploit could allow the attacker to cause database errors and cause the device to become unresponsive to web-based management. Manual intervention is required to free filesystem resources and return the device to an operational state.

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 · moderate confidence

This is a resource exhaustion vulnerability in Cisco FDM where authenticated remote attackers can upload excessive files to fill up the filesystem. The vulnerability stems from insufficient filesystem usage management controls. Successful exploitation causes database errors and makes the device unresponsive to web-based management, requiring manual intervention to recover.

MitigationRestrict and monitor authenticated access to the FDM web interface, implement filesystem usage alerts, and consider network segmentation to limit exposure. Apply any Cisco-provided patches when available.

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
Firepower Device ManagerApplication
Affected:>= 6.4.0, < 6.4.0.12>= 6.5.0, < 6.6.4>= 6.7.0, < 6.7.0.2

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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. Check the installed FDM version
    Log into the FDM web interface and navigate to Device > Dashboard or System > About to view the software version. Alternatively, access the device CLI and run the 'show version' command.
    Affected if The version falls within these ranges: 6.4.0 through 6.4.0.11, 6.5.0 through 6.6.3, or 6.7.0 through 6.7.0.1 (i.e., version is >= 6.4.0 but < 6.4.0.12, OR >= 6.5.0 but < 6.6.4, OR >= 6.7.0 but < 6.7.0.2).
  2. Verify authenticated access to FDM is exposed
    Determine whether the FDM web interface is accessible from untrusted networks. Review access lists, NAT rules, or VPN policies that govern who can reach the FDM HTTPS port (typically port 443). Check if remote management is enabled for external interfaces.
    Affected if The FDM web interface is reachable by unauthenticated or untrusted users, or by authenticated users who should not have file upload privileges.
  3. Check current filesystem usage
    Access the FDM CLI and run commands such as 'show disk' or 'show filesystem' to view available disk space. In the FDM web interface, navigate to Device > Dashboard and observe storage utilization metrics.
    Affected if Filesystem usage is at or near 100%, or there are alerts indicating storage is critically low.
  4. Look for symptoms of exploitation
    Attempt to access the FDM web interface and verify it loads normally. Check system logs for database errors or messages related to disk full conditions. Verify the device responds to management commands.
    Affected if The FDM web interface is unresponsive, loads with database errors, or CLI commands show the device is in a degraded state due to disk exhaustion.

You are affected if the FDM version is in the vulnerable range AND the device is accessible to authenticated attackers AND you observe filesystem exhaustion symptoms.

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
Upgrade available Upgrade to 6.4.0.12 / 6.6.4 / 6.7.0.2 or later
Fixed in 6.4.0.126.6.46.7.0.2
Interim mitigation

Restrict and monitor authenticated access to the FDM web interface, implement filesystem usage alerts, and consider network segmentation to limit exposure. Apply any Cisco-provided patches when available.

Fix this in Firepower Device Manager Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
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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-2021-1489 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
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