HTML sanitizer is written in PHP, aiming to provide XSS-safe markup based on explicitly allowed tags, attributes and values. In versions prior to 1.5.0 or 2.1.1, malicious markup used in a sequence with special HTML CDATA sections cannot be filtered and sanitized due to a parsing issue in the upstream package masterminds/html5. This allows bypassing the cross-site scripting mechanism of typo3/html-sanitizer. The upstream package masterminds/html5 provides HTML raw text elements (`script`, `style`, `noframes`, `noembed` and `iframe`) as DOMText nodes, which were not processed and sanitized further. None of the mentioned elements were defined in the default builder configuration, that's why only custom behaviors, using one of those tag names, were vulnerable to cross-site scripting. This issue has been fixed in versions 1.5.0 and 2.1.1.

The package express-xss-sanitizer before 1.1.3 are vulnerable to Prototype Pollution via the allowedTags attribute, allowing the attacker to bypass xss sanitization.

The typo3/html-sanitizer package is an HTML sanitizer, written in PHP, aiming to provide XSS-safe markup based on explicitly allowed tags, attributes and values. Due to a parsing issue in the upstream package `masterminds/html5`, malicious markup used in a sequence with special HTML comments cannot be filtered and sanitized. This allows for a bypass of the cross-site scripting mechanism of `typo3/html-sanitizer`. This issue has been addressed in versions 1.0.7 and 2.0.16 of the `typo3/html-sanitizer` package. Users are advised to upgrade. There are no known workarounds for this issue.

The package sanitize-html before 2.7.1 are vulnerable to Regular Expression Denial of Service (ReDoS) due to insecure global regular expression replacement logic of HTML comment removal.

lettersanitizer is a DOM-based HTML email sanitizer for in-browser email rendering. All versions of lettersanitizer below 1.0.2 are affected by a denial of service issue when processing a CSS at-rule `@keyframes`. This package is depended on by [react-letter](https://github.com/mat-sz/react-letter), therefore everyone using react-letter is also at risk. The problem has been patched in version 1.0.2.

# Possible XSS Vulnerability in Rails::Html::SanitizerThere is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.This vulnerability has been assigned the CVE identifier CVE-2022-32209.Versions Affected: ALLNot affected: NONEFixed Versions: v1.4.3## ImpactA possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both `select` and `style` elements.Code is only impacted if allowed tags are being overridden. This may be done via application configuration:```ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]```see https://guides.rubyonrails.org/configuring.html#configuring-action-viewOr it may be done with a `:tags` option to the Action View helper `sanitize`:```<%= sanitize @comment.body, tags: ["select", "style"] %>```see https://api.rubyonrails.org/classes/ActionView/…

The package @braintree/sanitize-url before 6.0.0 are vulnerable to Cross-site Scripting (XSS) due to improper sanitization in sanitizeUrl function.

svg-sanitizer is a SVG/XML sanitizer written in PHP. A cross-site scripting vulnerability impacts all users of the `svg-sanitizer` library prior to version 0.15.0. This issue is fixed in version 0.15.0. There is currently no workaround available.

The OWASP Java HTML Sanitizer before 20211018.1 does not properly enforce policies associated with the SELECT, STYLE, and OPTION elements.

Apostrophe Technologies sanitize-html before 2.3.2 does not properly validate the hostnames set by the "allowedIframeHostnames" option when the "allowIframeRelativeUrls" is set to true, which allows attackers to bypass hostname whitelist for iframe element, related using an src value that starts with "/\\example.com".