CVE-2025-59940: 
Python vulnerability analysis and mitigation

mkdocs-include-markdown-plugin, a Markdown includer plugin for Mkdocs, contains a vulnerability in versions 7.1.7 and below where unvalidated input can collide with substitution placeholders. The vulnerability was discovered and disclosed in September 2025, identified as CVE-2025-59940 (GitHub Advisory).

The vulnerability stems from improper input validation (CWE-20) where unvalidated input could collide with placeholder content. The issue occurs because the plugin fails to properly escape placeholder characters in input text, potentially allowing attackers to manipulate the content processing. The vulnerability has been assigned a CVSS v3.1 base score of 6.5 (Medium) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L, indicating it is network accessible with low attack complexity and requires no privileges or user interaction (GitHub Advisory).

The vulnerability has a low to moderate impact on system integrity and availability. While it doesn't affect confidentiality, it could allow attackers to manipulate content processing through input that matches placeholder patterns (GitHub Advisory).

The vulnerability has been fixed in version 7.1.8 of mkdocs-include-markdown-plugin. The fix involves escaping placeholder characters in input with text.replace(STX, '\u0002').replace(ETX, '\u0003') to prevent raw STX and ETX matches. Users should upgrade to version 7.1.8 or later to address this vulnerability (GitHub Commit).