matthiask/html-sanitizer · Security
Arbitrary HTML present after sanitization because of unicode normalization
- GHSA ID
- GHSA-wvhx-q427-fgh3
- CVE ID
- CVE-2024-34078
- Severity
- high
- Published
- Updated
Description
Impact
If using keep_typographic_whitespace=False (which is the default), the sanitizer normalizes unicode to the NFKC form at the end. Some unicode characters normalize to chevrons; this allows specially crafted HTML to escape sanitization.
Patches
The problem has been fixed in 2.4.2.
Workarounds
Set keep_typographic_whitespace=True explicitly, or normalize to NFKC yourself earlier.