CVE-2018-11499
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 · uneditedA use-after-free vulnerability exists in handle_error() in sass_context.cpp in LibSass 3.4.x and 3.5.x through 3.5.4 that could be leveraged to cause a denial of service (application crash) or possibly unspecified other impact.
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 confidenceA use-after-free vulnerability exists in the handle_error() function in sass_context.cpp in LibSass versions 3.4.x and 3.5.x through 3.5.4. This memory corruption flaw occurs when memory is accessed after being freed, potentially allowing denial of service through application crashes or potentially other unspecified impact.
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>= 3.4.0, <= 3.5.4CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Locate LibSass installationSearch for the sassc binary or libsass library in common paths such as /usr/bin/sassc, /usr/local/bin/sassc, or check package managers (npm list, gem list, pip list) for node-sass, sassc, or libsass bindingsAffected if LibSass or any tool using it (e.g., sassc, node-sass) is found on the system
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Identify the installed LibSass versionRun 'sassc --version' or check the version through the package manager that installed it (e.g., npm list node-sass, gem list sassc)Affected if A version number is returned by the tool or package manager
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Compare version against affected rangeCheck if the installed version falls within >= 3.4.0 and <= 3.5.4Affected if The installed version is 3.4.0, 3.4.1, 3.4.2, 3.4.3, 3.4.4, 3.4.5, 3.4.6, 3.4.7, 3.4.8, 3.4.9, 3.5.0, 3.5.1, 3.5.2, 3.5.3, or 3.5.4
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Verify if Sass compilation triggers the vulnerabilityCompile a Sass file that would trigger an error condition, as the flaw occurs in the handle_error() function during error handlingAffected if The compilation process crashes or exhibits undefined behavior during error handling with an affected LibSass version
You are affected if LibSass (sassc, node-sass, or any libsass-based tool) is installed with a version between 3.4.0 and 3.5.4 inclusive.
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.
dbcve · scopedUpdate LibSass to version 3.5.5 or later to patch the vulnerability. If immediate updating is not feasible, limit processing to trusted Sass files and monitor for crashes.
LibSass 3.5.5 or later (including 3.6.x stable releases)
- Identify all applications or projects that depend on LibSass version 3.4.0 through 3.5.4
- Update the LibSass dependency in your project's package manager (npm, gem, or other) to version 3.5.5 or later
- Run your build process to verify the upgrade does not introduce issues
- Test the application functionality to ensure the Sass compilation still works correctly
- Rebuild and redeploy any binaries or containers that include LibSass
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing4.0 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 $3,648.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-11499 — 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-2018-11499 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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