CVE-2026-7808
Severity CVSS v4.0:
CRITICAL
Type:
CWE-20
Input Validation
Publication date:
23/08/2026
Last modified:
23/08/2026
Description
justhtml before 1.16.0 contains multiple HTML sanitization bypass issues that can allow active/dangerous content (e.g., script or style) to survive sanitization, potentially leading to cross-site scripting. The issues primarily affect advanced usage rather than the default JustHTML(..., sanitize=True) path for ordinary parsed HTML: mutating or reusing sanitization policy objects (including exported defaults) could weaken later sanitization; programmatic DOM input to sanitize()/sanitize_dom() could miss mixed-case tag names (e.g., ScRiPt, StYlE); crafted programmatic doctype names could serialize into active markup; and custom policies preserving SVG or MathML could allow animation elements, presentation attributes with external url(...) references, or DOM trees mislabeled as namespace="html" to bypass foreign-content checks. Fixed in 1.16.0.
Impact
Base Score 4.0
9.30
Severity 4.0
CRITICAL
Base Score 3.x
9.80
Severity 3.x
CRITICAL