CVE-2026-5389Medium· 6.1▾ Sunlitjusthtml 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 fixe…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 33.6 · likelihood 0 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
Exploit-prediction probability, daily snapshots since Aug 24.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.2%
0.2% → 0.3%
Last analysed / modified upstream
— → 6.1
high → medium
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 generated Markdown is rendered by CommonMark or GFM-style renderers.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
justhtml < 1.13.0Patched in:
justhtml 1.13.0Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2026-6827Medium· 6.1justhtml before 1.17.0 contains multiple security issues in sanitization, serialization, and programmatic DOM handling
CVE-2026-9769High· 7.5justhtml through 1.9.1 (fixed in 1.10.0) is vulnerable to uncontrolled recursion leading to denial of service
CVE-2026-4671High· 7.5justhtml before 1.18.0 contains multiple low-severity denial-of-service issues in CSS selector handling and linkification
CVE-2026-5751Medium· 6.1justhtml 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 al…
CVE-2026-8630MediumJustHTML Affected by Mutation XSS via Literal Text Serialization in Raw Text Elements (style/script)
CVE-2026-77088Medium· 6.1justhtml versions 0.9.0 through 1.21.0 contain a cross-site scripting vulnerability in to_markdown() where inline code spans fail to account for blank lines as block boundaries