Impact

If pdf.js is used to load a malicious PDF, and PDF.js is configured with isEvalSupported set to true (which is the default value), unrestricted attacker-controlled JavaScript will be executed in the context of the hosting domain.

Patches

The patch removes the use of eval:
mozilla/pdf.js#18015

Workarounds

Set the option isEvalSupported to false.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1893645

References

• GHSA-wgrm-67xf-hhpq
• mozilla/pdf.js#18015
• mozilla/pdf.js@85e64b5
• https://bugzilla.mozilla.org/show_bug.cgi?id=1893645