title: HtmlSanitizer vulnerable to Cross-site Scripting in Foreign Content
description: HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. The vulnerability occurs in configurations where foreign content is allowed, i.e. either `svg` or `math` are in the list of allowed elements. In the case an application sanitizes user input with a vulnerable configuration, an attacker could bypass the sanitization and inject arbitrary HTML, including JavaScript code. Note that in the default configuration the vulnerability is not present. The vulnerability has been fixed in versions 8.0.723 and 8.1.722-beta (preview version).
problem types: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
affected:
{
vendor: mganss
product: HtmlSanitizer
versions:
version: < 8.0.723, status: affected
version: >= 8.1.0-beta, < 8.1.722-beta, status: affected
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 6.1
baseSeverity: MEDIUM
confidentialityImpact: LOW
integrityImpact: LOW
privilegesRequired: NONE
scope: CHANGED
userInteraction: REQUIRED
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
version: 3.1
]