CVE-2026-77088
Medium
Description
justhtml 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. Attackers can inject blank lines into code or pre element text to break the inline span, causing sanitized HTML to be emitted unescaped and re-parsed as live Markdown by compliant renderers.
SeverityMedium
CVSS6.1
Exploit probability—
ProductJusthtml
PublishedAug 23, 2026
First seenAug 23, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Update
- justhtml1.22.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| justhtmlPyPI | 0.9.0 ≤ v < 1.22.0 | 1.22.0 |
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