Arbitrary JavaScript execution due to using outdated libraries

Summary

gradio-pdf projects with dependencies on the pdf.js library are vulnerable to CVE-2024-4367, which allows arbitrary JavaScript execution.

PoC

1. Generate a pdf file with a malicious script in the fontmatrix. (This will run alert(‘XSS’).)
   poc.pdf

2. Run the app. In this PoC, I’ve used the demo for a simple proof.
   

3. Upload a PDF file containing the script.
   

4. Check that the script is running.
   

Impact

Malicious scripts can be injected into the code, and when linked with vulnerabilities such as CSRF, it can cause even greater damage. In particular, It can become a source of further attacks, especially when linked to social engineering.

Mitigation

Upgrade the pdf.js to v4.2.67, which removes the vulnerability. (or set the option isEvalSupported to false.)

Reference

1. https://codeanlabs.com/blog/research/cve-2024-4367-arbitrary-js-execution-in-pdf-js/
2. https://github.com/mozilla/pdf.js/pull/18015