{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27166","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-02-18T00:18:53.962Z","datePublished":"2026-03-19T20:29:22.570Z","dateUpdated":"2026-03-21T03:31:58.296Z"},"containers":{"cna":{"title":"Discourse vulnerable to HTML injection via prohibited iframe URLs","problemTypes":[{"descriptions":[{"cweId":"CWE-80","lang":"en","description":"CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.1,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2","tags":["x_refsource_CONFIRM"],"url":"https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2"},{"name":"https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925","tags":["x_refsource_MISC"],"url":"https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925"}],"affected":[{"vendor":"discourse","product":"discourse","versions":[{"version":"< 2026.3.0-latest.1","status":"affected"},{"version":">= 2026.2.0-latest, < 2026.2.1","status":"affected"},{"version":">= 2026.1.0-latest, < 2026.1.2","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-03-19T20:29:22.570Z"},"descriptions":[{"lang":"en","value":"Discourse is an open source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1 and  2026.1.2, insufficient cleanup in the default Codepen allowed iframes value allows an attacker to trick a user into changing the URL of the main page. This issue has been fixed in versions 2026.3.0-latest.1, 2026.2.1 and  2026.1.2. To workaround this issue, remove Codepen from the list of allowed iframes."}],"source":{"advisory":"GHSA-h653-cq78-vjj2","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-21T03:31:46.439342Z","id":"CVE-2026-27166","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-21T03:31:58.296Z"}}]}}