DocViewer failing to display PNG and JPEG files

Issue Documented: 2025-10-30
Canvas

This behavior has been resolved and deployed to the production environment as of 11/19/25.

Description

Specific submissions previewed via DocViewer cause the page to freeze.

Expected Behavior

Opening file previews via DocViewer should not cause the page to freeze

Workaround

Creating the documents again fixes the issue.

Steps to Reproduce

Prerequisites: A course containing a File Upload assignment and a student

  1. As the student, upload multiple files to the Assignment
  2. Submit the files
  3. View the SpeedGrader or DocViewer previews for the files
  4. Notice that some may end up repeatedly throwing two errors in the console, never loading and causing the page to freeze
    1. If this is not the case, repeat from step 1

Additional Info

FOO-5904

Known issues indicate notable behaviors that have been escalated to the Canvas engineering team. Known issues are not a guarantee for an immediate resolution. This document is for informational purposes only and does not replace the Support process. If you are encountering the behavior outlined in this document, please ensure you have submitted a Support case (per your institution's escalation process) so Canvas Support can adequately gauge the overall customer impact and prioritize appropriately.

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