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RackApplication · Rack Project

CVE-2018-16470

HIGH · 7.5 CVSS v3.0 Published 2018-11-13
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
There is a possible DoS vulnerability in the multipart parser in Rack before 2.0.6. Specially crafted requests can cause the multipart parser to enter a pathological state, causing the parser to use CPU resources disproportionate to the request size.

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 denial of service vulnerability exists in the multipart parser of Rack versions prior to 2.0.6. Specially crafted multipart requests can trigger a pathological parsing state that causes disproportionate CPU consumption relative to the request size, enabling attackers to exhaust server resources.

MitigationUpgrade Rack to version 2.0.6 or later to resolve the vulnerability in the multipart parser.

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
RackApplication
Affected:= 2.0.4= 2.0.5

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 installed Rack version
    Run `gem list rack` or inspect your Gemfile.lock to find the rack gem version
    Affected if Version is 2.0.4 or 2.0.5 specifically
  2. Confirm multipart request handling is in use
    Review application code for multipart form submissions, file uploads, or parameters that accept file attachments. Check Rack handler configuration for multipart parser middleware.
    Affected if The application accepts or processes multipart form data or file uploads
  3. Check for direct Rack::Multipart usage
    Inspect application code for direct usage of Rack::Multipart module or examine the Rack version bundled in the application dependencies.
    Affected if Rack handles multipart parsing and the version is within the affected range

The environment is affected only if Rack version 2.0.4 or 2.0.5 is installed AND the application processes multipart requests.

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

Upgrade Rack to version 2.0.6 or later to resolve the vulnerability in the multipart parser.

Fix this in Rack Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,010
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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-2018-16470 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
  • No spam, self-promotion, credentials, or personal data