{"id":"CVE-2026-72721","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-72721","generatedAt":"2026-10-28T00:17:05.652Z","title":"Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Onebox::DomainChecker.is_blocked? compares hostnames and SiteSetting.blocked_onebox_domains entries case-sensitively, allowing an attacker to bypass configured Onebox domain restrictions by changing…","description":"Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, Onebox::DomainChecker.is_blocked? compares hostnames and SiteSetting.blocked_onebox_domains entries case-sensitively, allowing an attacker to bypass configured Onebox domain restrictions by changing character casing in a redirect target hostname. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.","published":"2026-08-10T16:19:49.000Z","lastModified":"2026-09-08T20:54:38.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},"cwe":["CWE-178"],"affected":[],"epss":{"score":0.00585,"percentile":0.47697,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.58%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/discourse/discourse/commit/a3e10759fef47f03d450649bb51d9e84f4c68b8f","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/commit/c2eb6b0e5597d6f28f4be739b83300bc9c69e3cd","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/commit/caa615c371b1696982ee11ac8f3558f0f8ced584","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/commit/f503971d311b7b0dfdb751ee8cfd67e8cb99f5c5","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/pull/42091","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/pull/42092","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/pull/42093","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/pull/42094","source":"security-advisories@github.com"},{"url":"https://github.com/discourse/discourse/security/advisories/GHSA-3x7x-24rq-h5j6","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72721","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}