{"id":"BIT-discourse-2026-33410","summary":"Discourse hardens chat DM channel creation and expansion","details":"Discourse is an open-source discussion platform. Versions prior to 2026.3.0, 2026.2.1, and 2026.1.2 have two authorization issues in the chat direct message API. First, when creating a direct message channel or adding users to an existing one, the `target_groups` parameter was passed directly to the user resolution query without checking group or member visibility for the acting user. An authenticated chat user could craft an API request with a known private/hidden group name and receive a channel containing that group's members, leaking their identities. Second, `can_chat?` only checked group membership, not the `chat_enabled` user preference. A chat-disabled user could create or query DM channels between other users via the direct messages API, potentially exposing private `last_message` content from the serialized channel response. Versions 2026.3.0, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.","aliases":["CVE-2026-33410","GHSA-2m5j-6v2r-cq2h"],"modified":"2026-09-08T08:46:29.293766496Z","published":"2026-03-27T07:11:02.112Z","database_specific":{"cpes":["cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"],"severity":"Medium"},"references":[{"type":"ADVISORY","url":"https://github.com/discourse/discourse/security/advisories/GHSA-2m5j-6v2r-cq2h"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33410"}],"affected":[{"package":{"name":"discourse","ecosystem":"Bitnami","purl":"pkg:bitnami/discourse"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2026.1.0"},{"fixed":"2026.1.2"},{"introduced":"2026.2.0"},{"fixed":"2026.2.1"},{"introduced":"2026.3.0"},{"fixed":"2026.3.0"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/discourse/BIT-discourse-2026-33410.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"}]}],"schema_version":"1.9.0"}