Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the signup flow could allow newly registered users to set primary_group_id and gain whisper-group privileges without legitimate group membership on sites with whispers_allowed_groups configured. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
https://github.com/discourse/discourse/security/advisories/GHSA-vmwq-jvxx-jwfx
https://github.com/discourse/discourse/releases/tag/v2026.6.0
https://github.com/discourse/discourse/releases/tag/v2026.5.1
https://github.com/discourse/discourse/releases/tag/v2026.4.2
https://github.com/discourse/discourse/releases/tag/v2026.1.5
https://github.com/discourse/discourse/commit/6fc7e6cf04422fc3f9d1c99134803071e983ff0a
https://github.com/discourse/discourse/commit/5418e3027dba109e27a4796463686d61e190ac29
https://github.com/discourse/discourse/commit/0f50a07a6ef4b33f3f826ce6d7bf6d7bd16912d8
https://github.com/discourse/discourse/commit/012796ac28c85b30aa233c5ef042fc66efff8126