CVE-2026-77088

justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in tomarkdown where inline code spans fail to account for blank lines as block boundaries. Attackers can inject blank lines into code or pre element text to break the inline span, causing sanitized HTML to be...

CVE-2026-77088 justhtml 0.9.0 through 1.21.0 Cross-Site Scripting via code-span

justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in tomarkdown where inline code spans fail to account for blank lines as block boundaries. Attackers can inject blank lines into code or pre element text to break the inline span, causing sanitized HTML to be...

justhtml: to_markdown() code-span blank-line breakout enables XSS

justhtml: tomarkdown code-span blank-line breakout enables XSS Summary In justhtml 0.9.0 through 1.21.0, tomarkdown renders text and text inside a link as an inline Markdown code span whose only protection is backtick-fence length. A blank line \n\n in that text terminates the inline span in any...

Improper Encoding or Escaping of Output

Overview justhtml is an A pure Python HTML5 parser that just works. Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output in the tomarkdown process. An attacker can inject malicious HTML or script into rendered Markdown by including a blank line within the te...