CVE-2012-0839
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 · uneditedOCaml 3.12.1 and earlier 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 confidenceOCaml 3.12.1 and earlier contains a hash collision vulnerability where the runtime computes hash values without randomization, allowing context-dependent attackers to predictably trigger hash collisions by crafting specific input. This causes excessive CPU consumption when the application processes the malicious input through hash table operations, leading to 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<= 3.12.1= 1.07= 2.02= 2.04= 2.99= 3.00= 3.01= 3.02= 3.03= 3.04= 3.05= 3.06CVSS 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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Determine installed OCaml versionRun 'ocaml -version' or 'ocamlc -version' to see the OCaml compiler/runtime version installed in your environmentAffected if The version displayed is 3.12.1 or earlier, or matches any of these: 1.07, 2.02, 2.04, 2.99, 3.00, 3.01, 3.02, 3.03, 3.04, 3.05, 3.06
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Identify OCaml applications and servicesReview your environment for applications or services built with OCaml that process external input; check running processes or application dependencies for OCaml-based codeAffected if You have OCaml applications or services that accept external input and use OCaml's hash table data structures (Hashtbl module or Stdlib.Hashtbl)
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Check if hash randomization is availableConsult your OCaml version's documentation or release notes to determine if hash randomization was implemented; for 3.12.1 and earlier, no randomization existsAffected if Your OCaml version predates the fix and provides no hash randomization feature, meaning hash values for identical strings are deterministic across process restarts
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Assess input exposure to hash tablesReview application code or architecture to determine if untrusted input is used as keys in OCaml hash tables (e.g., Hashtbl.add, Hashtbl.find, or similar functions)Affected if External or untrusted input flows directly into OCaml hash table operations without sanitization, creating a path for attackers to inject collision-generating payloads
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Monitor CPU usage patternsObserve CPU consumption of OCaml applications during processing of external input; hash collision attacks cause disproportionate CPU spikesAffected if CPU usage becomes excessively high or application becomes unresponsive when processing certain input patterns, indicating possible hash collision attack
Your environment is affected if you run OCaml version 3.12.1 or earlier and have applications that pass external input directly into OCaml hash table operations without hash randomization.
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 OCaml that implements hash randomization, or alternatively implement application-layer rate limiting and input validation to detect and block collision-generating payloads before they reach hash table operations.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2012-0839 — 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-2012-0839 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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- Version or environment caveats, and links to real fixes
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