{"id":"CVE-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-latest.1, 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-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.","aliases":["BIT-discourse-2026-33410","GHSA-2m5j-6v2r-cq2h"],"modified":"2026-08-12T03:51:46.279803951Z","published":"2026-03-19T21:57:27.176Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-863"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33410.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33410.json"},{"type":"ADVISORY","url":"https://github.com/discourse/discourse/security/advisories/GHSA-2m5j-6v2r-cq2h"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33410"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/discourse/discourse","events":[{"introduced":"322d3c0ac6a8f133b3f82875e9dbbe310f638c1b"},{"fixed":"808b2ac23d8ff421563b40203091026732471c60"},{"introduced":"f7cec86997edc21d6074ceb7666f7e2e6e1b1fdf"},{"fixed":"f38464e46df1b8c51f7d60826502476908d6bb2b"},{"introduced":"896e810e1b296478bba91559a8fc89a9926f11fe"},{"last_affected":"896e810e1b296478bba91559a8fc89a9926f11fe"}],"database_specific":{"cpe":["cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*","cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*"],"extracted_events":[{"introduced":"2026.1.0"},{"fixed":"2026.1.2"},{"introduced":"2026.2.0"},{"fixed":"2026.2.1"},{"introduced":"2026.3.0"},{"last_affected":"2026.3.0"}],"source":["CPE_RANGE","CPE_STRING"]}}],"versions":["2026.3.0","= 2026.3.0-latest","v2026.1.1","v2026.2.0","v2026.3.0-latest","v2026.1.0","stable","esr","v2026.2.0-latest","v2026.1.0-latest"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33410.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N"}]}