{"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": "2026-03-19T20:29:22.570Z"}, "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"}}}}

{}

{"cveTags": [], "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."}], "id": "CVE-2026-27166", "lastModified": "2026-03-19T21:17:08.740", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.3, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-03-19T21:17:08.740", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/commit/c4762a4fac2f61f52f325396b11d3aeb955ea925"}, {"source": "security-advisories@github.com", "url": "https://github.com/discourse/discourse/security/advisories/GHSA-h653-cq78-vjj2"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-80"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}