Discourse escaping & in Onebox

loic · January 16, 2026, 10:45am

We’ve just merged a patch that addresses that particular problem (it should be resolved for all Oneboxes):

github.com/discourse/discourse

FIX: Don't escape HTML entities twice in oneboxes

main ← loic/fix-double-escape-onebox

merged 10:40AM - 16 Jan 26 UTC

Flink

+32 -25

Sometimes, HTML entities can be escaped twice, typically when getting sanitized …data from our `Onebox::OpenGraph` class then providing that value to a template. We’re using the Mustache gem to process the Onebox templates, and it will automatically escape HTML entities. This is usually not a problem, but it is for things like ampersands. For example, if the value we provide to the template is `&`, then Mustache will convert it to `&amp;`. This PR fixes that behavior by decoding the result of the sanitization we apply in `Onebox::OpenGraph`. That way, templates will get `&` instead of `&`, thus there won’t be any double escaping.

Topic		Replies	Views
One Box url encoding of already encoded comma Bug	4	1111	June 27, 2019
Onebox breaks if there's chinese text in URL Bug	14	1747	September 27, 2017
Links improperly escaped Bug	4	765	August 12, 2019
Onebox description not showing if first character is double quotation mark Support	1	290	July 18, 2022
Onebox links with ampersands don't encode correctly Bug	2	906	September 7, 2017

Discourse escaping & in Onebox

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