CVE-2026-7808: Improper Input Validation

justhtml before 1.16.0 contains multiple HTML sanitization bypass issues that can allow active/dangerous content e.g., script or style to survive sanitization, potentially leading to cross-site scripting. The issues primarily affect advanced usage rather than the default JustHTML..., sanitize=Tru...

CVE-2026-77088: Improper Neutralization of Input During Web Page Generation

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-2026-74793: Improper Neutralization of Input During Web Page Generation

justhtml before 3.11.0 contains a cross-site scripting vulnerability where the default sanitizer bypasses event handler removal in selectedcontent projections. Attackers can inject SVG or MathML elements with event handlers that are cloned and reinserted into output without sanitization, enabling...

CVE-2026-6827: Improper Neutralization of Input During Web Page Generation

justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling. When custom policies preserve foreign namespaces SVG/MathML, dangerous content such as HTML integration points SVG , MathML and mutation-XSS parser-differential payloads could...

CVE-2026-4671: Uncontrolled Resource Consumption

justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification. Applications that evaluate attacker-controlled selector strings via query, matches, or selector-based transforms, run selector matching over very large untrusted documents,...

PT-2026-79769

justhtml before 1.15.0 contains multiple security issues in URL sanitization helpers clean url value/clean url in js string, HTML serialization, Markdown passthrough html passthrough=True, and several custom sanitization-policy edge cases. Depending on configuration, an attacker can bypass...

CVE-2026-5389: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the tomarkdown function when serializing attacker-controlled pre content. Attackers can place backticks inside sanitized pre elements to break out of fixed-length code fences, allowing raw HTML to execute when the...

PT-2026-79770

justhtml versions before 1.13.0 contain a cross-site scripting vulnerability in the to markdown function when serializing attacker-controlled pre content. Attackers can place backticks inside sanitized pre elements to break out of fixed-length code fences, allowing raw HTML to execute when the...

CVE-2026-5388: Improper Input Validation

justhtml before 1.15.0 contains multiple security issues in URL sanitization helpers cleanurlvalue/cleanurlinjsstring, HTML serialization, Markdown passthrough htmlpassthrough=True, and several custom sanitization-policy edge cases. Depending on configuration, an attacker can bypass sanitization ...

PT-2026-79776

justhtml versions are preserved, so untrusted input that is safe in to html — including entity-decoded text e.g. script or text from RCDATA/RAWTEXT-parsed elements like , , , and — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting wh...

PT-2026-79771

justhtml versions 1.13.0 and earlier contain a parser-differential / mutation cross-site scripting mXSS vulnerability when using a custom SanitizationPolicy that preserves foreign namespaces e.g., drop foreign namespaces=False with allowlisted SVG/MathML elements or raw-text containers such as...

PT-2026-79775

Name of the Vulnerable Software and Affected Versions justhtml versions prior to 1.16.0 Description Multiple HTML sanitization bypass issues allow active or dangerous content, such as script or style tags, to survive the sanitization process, potentially leading to cross-site scripting. These...

PT-2026-79773

Name of the Vulnerable Software and Affected Versions justhtml versions prior to 3.11.0 Description A cross-site scripting issue exists where the default sanitizer fails to remove event handlers within selectedcontent projections. This allows attackers to inject SVG or MathML elements containing...

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...

GHSA-JF6W-2MVX-633J 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...

any2htpy (>=0.1.4, <=0.2.2), article-extractor (>=0.5.8, <=0.5.9) +1 more potentially affected by unknown CVE via justhtml (>=0.35.0, <=1.14.0)

justhtml PYPI version =0.35.0, =0.1.4, =0.5.8, =0.1.0, =0.1.5 Source cves: unknown CVE Source advisory: GHSA-JF6W-2MVX-633J...

any2htpy (>=0.1.4, <=0.2.2), article-extractor (>=0.5.8, <=0.5.9) +1 more potentially affected by CVE-2026-77088 via justhtml (>=0.35.0, <=1.14.0)

justhtml PYPI version =0.35.0, =0.1.4, =0.5.8, =0.1.0, =0.1.5 Source cves: CVE-2026-77088 Source advisory: OSV:GHSA-JF6W-2MVX-633J...

any2htpy (>=0.1.4, <=0.2.2), article-extractor (>=0.5.8, <=0.5.9) +1 more potentially affected by unknown CVE via justhtml (>=0.35.0, <=1.14.0)

justhtml PYPI version =0.35.0, =0.1.4, =0.5.8, =0.1.0, =0.1.5 Source cves: unknown CVE Source advisory: SNYK:PYTHON-JUSTHTML-17670531...

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...

PT-2026-55844

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