CVE-2018-11547
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 · uneditedmd_is_link_reference_definition_helper in md4c 0.2.5 has a heap-based buffer over-read because md_is_link_label mishandles loop termination.
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 confidenceA heap-based buffer over-read vulnerability exists in md4c 0.2.5 within the md_is_link_reference_definition_helper function. The issue stems from md_is_link_label incorrectly handling loop termination conditions, causing the parser to read beyond allocated heap memory boundaries when processing markdown link labels.
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= 0.2.5CVSS 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
- 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.
-
Identify md4c library presenceSearch for md4c library files on the system (e.g., libmd4c, md4c.dll, or md4c shared objects) or check package managers for installed md4c packagesAffected if md4c version 0.2.5 is installed
-
Determine md4c versionRun version check command for md4c (e.g., md4c --version, or inspect library file metadata) or check the library file timestamp and compare to the 0.2.5 releaseAffected if The installed version is exactly 0.2.5
-
Inspect md_is_link_label functionIf source code is available, examine the md_is_link_label function in the source tree and look for loop termination logic within the function; verify if the boundary check logic is missing or incorrectAffected if The source code matches the vulnerable 0.2.5 version without the fix applied to loop termination conditions
-
Identify applications using md4cSearch for applications or services that link against md4c (e.g., static analysis tools, markdown processors, or documentation generators) and note their usage of link reference definitions in processed markdownAffected if An application using md4c 0.2.5 processes markdown input containing link labels
-
Check for markdown link label processingReview application logs or input feeds to determine if markdown containing link labels (syntax: [label] or [label]: url) is being parsed by the md4c libraryAffected if md4c 0.2.5 is actively parsing markdown with link label syntax
The environment is affected if md4c version 0.2.5 is installed and is being used to parse markdown input containing link labels.
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 md4c to version 0.3.0 or later which contains the fix. If upgrading is not immediately feasible, implement input validation limits on link label length before passing to the parser.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-11547 — 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-2018-11547 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data