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.
History

Sat, 21 Mar 2026 05:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 20 Mar 2026 09:00:00 +0000

Type Values Removed Values Added
First Time appeared Discourse
Discourse discourse
Vendors & Products Discourse
Discourse discourse

Thu, 19 Mar 2026 20:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Discourse vulnerable to HTML injection via prohibited iframe URLs
Weaknesses CWE-80
References
Metrics cvssV3_1

{'score': 4.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-03-19T20:29:22.570Z

Updated: 2026-03-21T03:31:58.296Z

Reserved: 2026-02-18T00:18:53.962Z

Link: CVE-2026-27166

cve-icon Vulnrichment

Updated: 2026-03-21T03:31:52.352Z

cve-icon NVD

Status : Undergoing Analysis

Published: 2026-03-19T21:17:08.740

Modified: 2026-03-20T13:39:46.493

Link: CVE-2026-27166

cve-icon Redhat

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