{"id":"CVE-2026-91132","published":"2026-09-24T17:17:08.723","lastModified":"2026-09-29T03:17:21.457","description":"Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.","cvssScore":4.3,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N","cwes":["CWE-346"],"vendors":[],"products":[],"references":[{"url":"https://github.com/discourse/discourse/commit/80968704c1acb1d2ea2c6011dbf6c02ff13238e5","tags":[]},{"url":"https://github.com/discourse/discourse/commit/d5ae0940707f95da5bc4562f7b544243e3103f8a","tags":[]},{"url":"https://github.com/discourse/discourse/commit/d88e02ceb2eede4d8b851d9fe8aef753f3aa40b9","tags":[]},{"url":"https://github.com/discourse/discourse/commit/db8064f2a2a2a3feb3308a1c932ac61d950c9e56","tags":[]},{"url":"https://github.com/discourse/discourse/pull/42882","tags":[]},{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-4q3q-hph3-3rvp","tags":[]}],"exploitRefs":[{"url":"https://github.com/discourse/discourse/commit/80968704c1acb1d2ea2c6011dbf6c02ff13238e5","tags":[]},{"url":"https://github.com/discourse/discourse/commit/d5ae0940707f95da5bc4562f7b544243e3103f8a","tags":[]},{"url":"https://github.com/discourse/discourse/commit/d88e02ceb2eede4d8b851d9fe8aef753f3aa40b9","tags":[]},{"url":"https://github.com/discourse/discourse/commit/db8064f2a2a2a3feb3308a1c932ac61d950c9e56","tags":[]},{"url":"https://github.com/discourse/discourse/pull/42882","tags":[]},{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-4q3q-hph3-3rvp","tags":[]}],"hasPoc":true,"ai":null}