CVE-2026-5389
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.1
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- EPSS probability
- 0.19%
- CWE
- CWE-80
- Published
- 2026-08-23
- Last modified
- 2026-08-24
Affected products
- EmilStenstrom justhtml
- EmilStenstrom justhtml
Weakness type
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