How to disable use of HTML5 canvas image data?

Support
1

After login to discourse forums, Tor Browser will show:

Will you allow forum.domain.org to use your HTML5 canvas image data? This may be used to uniquely identify your computer.

How to disable use of HTML5 canvas image data?

2

Does it show that on all Discourses? For example https://try.discourse.org?

3

No, I could not reproduce on https://try.discourse.org.

4

Then maybe the Discourse(s) you tried is doing some fingerprinting?

We aren’t by default in Discourse. Unless they’ve installed the discourse-fingerprinting plugin (or they did it manually in a theme).

2 Likes
5

Very strange. I am the admin of it and I didn’t add anything even remotely related to HTML5 canvas. (And I guess a server compromise to add HTML5 canvas is quite unlikely.) So I wouldn’t know what I did wrong.

Not using any plugins (except the default docker manager plugin).

Using default theme.

6

Yes, I can confirm I also noticed same on the Tor browser.

7

On try.discourse.org or on meta.discourse.org?

3 Likes
8

Can’t reproduce on neither.

In which forum is it happening for you?

  • In the forum where I am admin? (Don’t want to advertise it here, no need.)
  • Or you don’t know me (good, in this case, ha) and it is happening for you in another forum?

Does it happen for you in try.discourse.org or on meta.discourse.org?