Vulnerability Description
justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via to_markdown(). While a small set of Markdown metacharacters are escaped, characters such as < and > 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 <title>, <textarea>, <noscript>, and <plaintext> — can be emitted as raw HTML in the Markdown output, enabling a sanitizer bypass and potential cross-site scripting when that output is rendered.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45
- https://www.vulncheck.com/advisories/justhtml-before-sanitizer-bypass-via-markdo
- https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45
FAQ
What is CVE-2026-8445?
CVE-2026-8445 is a vulnerability with a CVSS score of 9.8 (CRITICAL). justhtml versions <= 1.11.0 (fixed in 1.12.0) do not sufficiently escape HTML-significant characters (angle brackets) in text nodes when converting a parsed document to Markdown via to_markdown(). Whi...
How severe is CVE-2026-8445?
CVE-2026-8445 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-8445?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.