CVE-2026-27166
March 19, 2026
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.
Affected Packages
https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) =v2026.3.0-latest <v2026.3.0-latest.1Fix Suggestion:
Update to version v2026.3.0-latest.1https://github.com/discourse/discourse.git (GITHUB):
Affected version(s) >=v2026.1.0-latest <v2026.1.2Fix Suggestion:
Update to version v2026.1.2Related Resources (2)
Do you need more information?
Contact UsCVSS v4
Base Score:
5.1
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
LOW
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
LOW
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
LOW
Subsequent System Availability
NONE
CVSS v3
Base Score:
4.1
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Weakness Type (CWE)
Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
EPSS
Base Score:
0.03
