RailsApplication · Rubyonrails
CVE-2014-3916
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 · uneditedThe str_buf_cat function in string.c in Ruby 1.9.3, 2.0.0, and 2.1 allows context-dependent attackers to cause a denial of service (segmentation fault and crash) via a long string.
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 confidenceThe str_buf_cat function in Ruby's string.c (affecting versions 1.9.3, 2.0.0, and 2.1) contains a flaw in handling long strings during concatenation. When processing an excessively long string, the function can trigger a segmentation fault, causing the Ruby interpreter to crash and resulting in denial of service.
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
RailsApplication
= 1.9.3= 2.0.0= 2.1.0CVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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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Check installed Ruby versionRun 'ruby --version' on the command line to determine the Ruby interpreter versionAffected if The version is 1.9.3, 2.0.0, or any 2.1.x version before the patch
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Identify Ruby interpreter in useLocate the Ruby binary used by the application: which ruby, or check the application's Ruby path configurationAffected if The identified Ruby binary matches an affected version from step 1
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Determine if string concatenation is usedReview application code for use of string concatenation operators (+, <<, concat) or String#concat method calls on user-controlled or large data sourcesAffected if The application concatenates strings from untrusted or large input sources
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Check for long string handlingAnalyze whether the application processes or concatenates strings that could exceed normal buffer sizes, particularly in loops or with data from external sourcesAffected if The application handles strings that could be excessively long before concatenation
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Test for crash condition if applicableIf the above conditions match, construct a test case with an intentionally long string (several MB) and attempt concatenation to observe if a segmentation fault occursAffected if A segmentation fault occurs during long string concatenation
The environment is affected if the installed Ruby version is 1.9.3, 2.0.0, or 2.1.x and the application concatenates long strings from untrusted or large input sources.
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 to a patched version of Ruby that addresses the str_buf_cat vulnerability. As a workaround, avoid concatenating extremely long strings in untrusted contexts until the upgrade is complete.
Fix this in Rails
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2014-3916 — 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-2014-3916 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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