EEF-CVE-2026-53427 Cross-site scripting in MDEx via unescaped highlight_lines_class code-fence attribute

Summary Improper Neutralization of Input During Web Page Generation 'Cross-site Scripting' vulnerability in leandrocp MDEx allows stored or reflected cross-site scripting via attacker-controlled Markdown. When syntax highlighting and full info-string forwarding render: \full\info\string: true\ ar...

CVE-2026-53427

The CVE-2026-53427 issue is a cross-site scripting vulnerability in leandrocp MDEx exposed via Markdown rendering. When render: full_info_string is enabled, the Lumis adapter copies a code fence’s highlight_lines_class info-string into per-line HTML class attributes, parsing key=value pairs via s...