CVE-2017-12962
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 · uneditedThere are memory leaks in LibSass 3.4.5 triggered by deeply nested code, such as code with a long sequence of open parenthesis characters, leading to a remote denial of service attack.
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 confidenceLibSass 3.4.5 contains a memory leak vulnerability in its parser when processing deeply nested code structures, specifically triggered by long sequences of open parenthesis characters. This causes progressive memory exhaustion 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= 3.4.5CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify LibSass installation locationLocate the LibSass library file (libsass.so on Linux, libsass.dll on Windows, or check package.json/node_modules for node-sass or sass-loader in Node.js projects)Affected if LibSass library files are present in the environment
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Determine installed LibSass versionRun `sassc --version` or check the version field in package.json for node-sass/sass, or use the system's package manager (e.g., `dpkg -l | grep libsass` or `rpm -qa | grep libsass`)Affected if The version reported is exactly 3.4.5
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Verify library file version stringIf a shared library exists, run `strings libsass.so | grep -i "3\.4\.5"` or check the binary metadata for version 3.4.5Affected if The binary contains version string 3.4.5 specifically
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Confirm application uses LibSass for SCSS processingReview application dependencies or configuration to confirm SCSS/SASS compilation uses LibSass (as opposed to Ruby Sass or Dart Sass)Affected if The application explicitly depends on LibSass or node-sass which bundles it
The environment is affected only if LibSass version 3.4.5 is installed and actively used for processing SCSS/SASS stylesheets containing deeply nested structures.
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 dataUpdate LibSass to a patched version beyond 3.4.5 that addresses the memory leak, or implement input validation to limit nesting depth before processing.
- Consultation2.0 h
- Implementation6.0 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 $3,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-12962 — 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-2017-12962 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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