Local File Read and SSRF vulnerability via img tags

[jmoritzc53]

Guidelines

• I understand that if I fail to provide all required details, this issue may be closed without review.

Description of the bug

There is a bug in the fetching of images which allows rendering local files into the PDF document. To exploit this issue an attacker needs to control the src attribute of an img tag.

mPDF version

8.1.2, 8.0.17

PHP Version and environment (server type, cli provider etc., enclosing libraries and their respective versions)

PHP 8.1, Ubuntu server

Reproducible PHP+CSS+HTML snippet suffering by the error

For further details, please reach out to johannes@cure53.de.

[nwse-ghm]

Issue might be closely related to #867, #868