{"id":"BIT-discourse-2026-72724","summary":"Discourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch","details":"Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before checking whether the user can preview the selected chat channel. An authenticated user can pair a public channel ID with a private thread ID in a /onebox.json request and obtain private thread message content. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.","aliases":["CVE-2026-72724","GHSA-8g98-fvfc-9w48"],"modified":"2026-08-17T08:10:41.231164716Z","published":"2026-08-17T05:44:26.455Z","database_specific":{"severity":"Medium","cpes":["cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*"]},"references":[{"type":"WEB","url":"https://github.com/discourse/discourse/commit/1276d7032af8803956c74ae87ccfd976938dcd75"},{"type":"WEB","url":"https://github.com/discourse/discourse/commit/45ab6d54076de9ca4965888974d4416d5b48e83c"},{"type":"WEB","url":"https://github.com/discourse/discourse/commit/49efe1d7f098f2ce7301908815a211cc9248270f"},{"type":"WEB","url":"https://github.com/discourse/discourse/commit/dc54846f0754799591717b6018343e49524e41ce"},{"type":"WEB","url":"https://github.com/discourse/discourse/pull/42091"},{"type":"WEB","url":"https://github.com/discourse/discourse/pull/42092"},{"type":"WEB","url":"https://github.com/discourse/discourse/pull/42093"},{"type":"WEB","url":"https://github.com/discourse/discourse/pull/42094"},{"type":"WEB","url":"https://github.com/discourse/discourse/security/advisories/GHSA-8g98-fvfc-9w48"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72724"}],"affected":[{"package":{"name":"discourse","ecosystem":"Bitnami","purl":"pkg:bitnami/discourse"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2026.1.6"},{"introduced":"2026.5.0"},{"fixed":"2026.5.2"},{"introduced":"2026.6.0"},{"fixed":"2026.6.1"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/discourse/BIT-discourse-2026-72724.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N"}]}],"schema_version":"1.9.0"}