RubyApplication · Ruby Lang
CVE-2011-4815
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 · uneditedRuby (aka CRuby) before 1.8.7-p357 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.
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 confidenceRuby (CRuby) before 1.8.7-p357 computes hash values without restricting the ability to trigger hash collisions predictably. This allows context-dependent attackers to cause a denial of service (CPU consumption) by sending crafted input that forces predictable hash collisions in hash tables used by the application.
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
RubyApplication
<= 1.8.7-p352= 1.8.7-p299= 1.8.7-p302= 1.8.7-p330= 1.8.7-p334CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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 checksWork through these to decide whether this CVE applies to you.
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Determine installed Ruby versionRun `ruby --version` or `ruby -v` in the environment where the Ruby application runsAffected if The version displayed is one of the affected versions: <= 1.8.7-p352, 1.8.7-p299, 1.8.7-p302, 1.8.7-p330, or 1.8.7-p334
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Identify if application processes external input into hash structuresReview application code for use of hashes (e.g., Hash[], {key: value}, or hashrocket syntax) populated from user-supplied data such as HTTP request parameters, JSON bodies, or query stringsAffected if The application uses external input to populate hash tables and the Ruby version is vulnerable as checked above
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Check for web-facing request handlingExamine whether the Ruby application accepts HTTP requests that could contain many parameter keys (e.g., via query strings, form data, or JSON payloads) which would be converted into a hashAffected if The application accepts and processes external HTTP parameters into hash structures and runs a vulnerable Ruby version
You are affected if your installed Ruby version is 1.8.7-p334 or earlier (including the specific patch versions p299, p302, p330) AND your application processes user-supplied input into hash tables, enabling an attacker to trigger predictable hash collisions and cause CPU exhaustion.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade Ruby to version 1.8.7-p357 or later. Additionally, consider implementing request rate limiting or web application firewall rules to mitigate hash collision attacks at the network boundary.
Fix this in Ruby
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-4815 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2011-4815 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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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