CVE-2026-8445
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| EmilStenstrom | justhtml | 0 < 1.12.0 | affected |
| EmilStenstrom | justhtml | 1.12.0 | unaffected |
Weaknesses
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
References
- https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-3rcm-vjrc-p45j
- https://www.vulncheck.com/advisories/justhtml-before-sanitizer-bypass-via-markdown
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