Advisories for Gem/Sanitize package

Sanitize is an allowlist-based HTML and CSS sanitizer. Using carefully crafted input, an attacker may be able to sneak arbitrary HTML and CSS through Sanitize starting with version 3.0.0 and prior to version 6.0.2 when Sanitize is configured to use the built-in "relaxed" config or when using a custom config that allows style elements and one or more CSS at-rules. This could result in cross-site scripting or other undesired behavior …

Sanitize is an allowlist-based HTML and CSS sanitizer. Versions 5.0.0 and later, prior to 6.0.1, is vulnerable to Cross-site Scripting. When Sanitize is configured with a custom allowlist that allows noscript elements, attackers are able to include arbitrary HTML, resulting in XSS (cross-site scripting) or other undesired behavior when that HTML is rendered in a browser. The default configurations do not allow noscript elements and are not vulnerable. This issue …

In Sanitize (RubyGem sanitize) there is a cross-site scripting vulnerability. When HTML is sanitized using Sanitize's relaxed config, or a custom config that allows certain elements, some content in a math or svg element may not be sanitized correctly even if math and svg are not in the allowlist.

When sanitize is used in combination with libxml2, a specially crafted HTML fragment can cause libxml2 to generate improperly escaped output, allowing attributes that are not specified in the allowlist to be used. This can allow HTML and JavaScript injection, which could result in XSS if the output is served to browsers.