CVE-2021-43794: Discourse

Medium severity, CVSS 5.3. EPSS: 1.1% chance of exploitation in the next 30 days.

Discourse is an open source discussion platform. In affected versions an attacker can poison the cache for anonymous (i.e. not logged in) users, such that the users are shown a JSON blob instead of the HTML page. This can lead to a partial denial-of-service. This issue is patched in the latest stable, beta and tests-passed versions of Discourse.

Affected products

• Discourse Discourse: before 2.7.11 (fixed in 2.7.11)

Published 2021-12-01. Last modified 2026-06-17.