GitHub Advisory DatabaseGHSA-WVHX-Q427-FGH3Arbitrary HTML present after sanitization because of unicode normalization
6.1 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.6 Medium
AI Score
Confidence
High
0.0004 Low
EPSS
Percentile
9.0%
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.
Affected configurations
| CPE | Name | Operator | Version |
|---|---|---|---|
| html-sanitizer | lt | 2.4.2 |
Related
6.1 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.6 Medium
AI Score
Confidence
High
0.0004 Low
EPSS
Percentile
9.0%