dbcve.org
Firepower System SoftwareApplication · Cisco

CVE-2018-0455

HIGH · 7.5 CVSS v3.0 Published 2018-10-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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 Server Message Block Version 2 (SMBv2) and Version 3 (SMBv3) protocol implementation for the Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause the device to run low on system memory, possibly preventing the device from forwarding traffic. It is also possible that a manual reload of the device may be required to clear the condition. The vulnerability is due to incorrect SMB header validation. An attacker could exploit this vulnerability by sending a custom SMB file transfer through the targeted device. A successful exploit could cause the device to consume an excessive amount of system memory and prevent the SNORT process from forwarding network traffic. This vulnerability can be exploited using either IPv4 or IPv6 in combination with SMBv2 or SMBv3 network traffic.

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 memory exhaustion vulnerability in Cisco Firepower System Software's SMBv2/SMBv3 protocol implementation. Incorrect SMB header validation allows unauthenticated remote attackers to send custom SMB file transfers that consume excessive system memory. This can prevent the SNORT intrusion prevention process from forwarding network traffic and may require a manual device reload to recover.

MitigationApply the Cisco patch when available. Until then, consider network segmentation to limit exposure to untrusted SMB traffic and monitor memory utilization on affected devices.

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 System SoftwareApplication
Affected:= 6.0= 6.0.1= 6.1.0= 6.2.0= 6.2.0.2= 6.2.1= 6.2.2= 6.2.3

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

CVSS:3.0/AV:N/AC:L/PR:N/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. Identify the device and software version
    Run 'show version' or access the Firepower management console to determine the Cisco Firepower System Software version
    Affected if The installed version matches any of: 6.0, 6.0.1, 6.1.0, 6.2.0, 6.2.0.2, 6.2.1, 6.2.2, or 6.2.3
  2. Verify SMBv2/SMBv3 inspection is enabled
    Check the Firepower policy configuration for any active SMB file inspection, file policy, or intrusion rule that inspects SMBv2/SMBv3 traffic
    Affected if SMB protocol inspection or file policies are applied to traffic that could receive malformed SMB packets from untrusted sources
  3. Confirm memory exhaustion symptoms
    Run 'show memory' or check the Firepower dashboard for abnormally high memory utilization, particularly in the Snort process
    Affected if Memory usage is excessively high or the Snort process shows memory allocation failures or restarts
  4. Check Snort process status
    Run 'show process cpu' or 'show module' to verify the Snort intrusion prevention process is running normally
    Affected if The Snort process has crashed, is unresponsive, or fails to forward traffic despite system availability

You are affected if your Cisco Firepower System Software version is between 6.0 and 6.2.3 inclusive and the device processes untrusted SMB traffic with file inspection 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.

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

Apply the Cisco patch when available. Until then, consider network segmentation to limit exposure to untrusted SMB traffic and monitor memory utilization on affected devices.

Fix this in Firepower System Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,504.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-0455 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2018-0455 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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