Debian LinuxOperating system · Debian
CVE-2018-11503
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 · uneditedThe isfootnote function in markdown.c in libmarkdown.a in DISCOUNT 2.2.3a allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted file, as demonstrated by mkd2html.
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 heap-based buffer over-read vulnerability exists in the isfootnote function in markdown.c of the DISCOUNT library (libmarkdown.a) version 2.2.3a. By providing a specially crafted markdown file to utilities like mkd2html, attackers can trigger the vulnerability, causing the application to read beyond allocated heap memory boundaries, resulting in a denial of service (crash).
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
Debian LinuxOperating system
= 8.0= 9.0= 2.2.3CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/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 DISCOUNT library versionRun 'markdown -v' or check the library file directly using 'dpkg -l libmarkdown2' (Debian) or inspect the binary/library file for version stringsAffected if Installed version equals 2.2.3 (or 2.2.3a)
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Locate mkd2html utilityCheck if mkd2html binary exists in PATH using 'which mkd2html' or 'find /usr -name mkd2html'Affected if mkd2html utility is present on the system
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Confirm markdown processing capabilityRun 'mkd2html --help' or 'mkd2html -V' to verify the utility can process markdown filesAffected if mkd2html is executable and can process input markdown files
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Check for isfootnote function usageInspect the markdown.c source if available, or verify the library handles footnote processing when converting markdown to HTMLAffected if Markdown files containing footnotes are processed by the vulnerable code path
The system is affected if DISCOUNT library version 2.2.3 is installed AND mkd2html or similar markdown utilities are used to process untrusted markdown files with footnote syntax.
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 to a patched version of DISCOUNT library if available, or implement proper bounds checking in the isfootnote function to validate buffer limits before memory access operations.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-11503 — 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-2018-11503 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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