Md4cApplication · Md4c Project

CVE-2018-11545

CRITICAL · 9.8 CVSS v3.0 Published 2018-05-29
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
md4c 0.2.5 has a heap-based buffer overflow in md_merge_lines because md_is_link_label mishandles the case of a link label composed solely of backslash escapes.

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 confidence

md4c 0.2.5 contains a heap-based buffer overflow in the md_merge_lines function caused by improper handling of link labels composed solely of backslash escape sequences in the md_is_link_label function, leading to memory corruption during markdown parsing.

MitigationUpgrade md4c to a patched version that addresses the link label parsing vulnerability; until then, validate and sanitize markdown input to reject malformed link labels with excessive backslash escapes.

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
Md4cApplication
Affected:= 0.2.5

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify md4c library version
    Locate the md4c library binary or inspect the version information from the compiled library (e.g., via library file properties, package manager query, or application dependency listing)
    Affected if The installed version is exactly 0.2.5
  2. Confirm markdown parsing usage
    Identify if any application or service links against md4c and processes markdown input
    Affected if md4c is loaded and actively parsing markdown content from external or untrusted sources
  3. Inspect input for link labels with backslash escapes
    Review markdown input being processed for patterns involving link labels (e.g., [text][]) containing backslash escape sequences
    Affected if The parsed markdown contains link labels composed solely of backslash escape sequences (e.g., multiple backslashes within square brackets)

A system is affected if it runs md4c version 0.2.5 and parses markdown input containing link labels with backslash escape sequences.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade md4c to a patched version that addresses the link label parsing vulnerability; until then, validate and sanitize markdown input to reject malformed link labels with excessive backslash escapes.

Recommended fix Moderate confidence

Latest stable md4c release (version 0.4.0 or later)

  1. 1. Identify all applications or systems that depend on md4c version 0.2.5
  2. 2. Update the md4c dependency to a version newer than 0.2.5 in your project's dependency manifest (e.g., package.json, requirements.txt, or similar)
  3. 3. Rebuild and recompile any applications that link against the md4c library
  4. 4. Verify the update by running your application's test suite, particularly any markdown parsing functionality
  5. 5. Deploy the updated application to production environments
Caveat Low risk - this is a bug fix for a security vulnerability; minor API changes between 0.2.5 and current versions are possible but unlikely to affect most use cases

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Md4c Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-11545 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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