Markdown output manipulation via placeholder collision
Published Sep 29, 2025 · Updated Sep 29, 2025
Improper input validation in mondeja mkdocs-include-markdown-plugin before 7.1.8 allows remote attackers to alter generated Markdown. The include processor stores included text behind predictable STX/ETX-delimited placeholders, then replaces the first matching token without escaping identical input text. Reachability requires attacker-controlled Markdown to enter a documentation build; a crafted placeholder redirects included content and leaves the intended include marker unresolved.
Summary
What happened
Improper input validation in mondeja mkdocs-include-markdown-plugin before 7.1.8 allows remote attackers to alter generated Markdown. The include processor stores included text behind predictable STX/ETX-delimited placeholders, then replaces the first matching token without escaping identical input text. Reachability requires attacker-controlled Markdown to enter a documentation build; a crafted placeholder redirects included content and leaves the intended include marker unresolved.
The record
- CVE
- CVE-2025-59940
- Published
- Sep 29, 2025
- Updated
- Sep 29, 2025
- Vendor
- mondeja
- Product
- mkdocs-include-markdown-plugin
- Classifications
- CWE-20
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 29, 2025CVE publishedPublication date reported by the CVE source.
- Sep 29, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 7.1.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream placeholder-collision regression caseproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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