Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-27166

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
19/03/2026
Last modified:
25/03/2026

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.

Impact

Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 4.10 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): Required
Scope (S): Changed
Confidentiality (C): None
Integrity (I): Low
Availability (A): None

Base Score 3.x
4.10
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.3.0 (excluding)
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.1.0 (including) 2026.1.2 (excluding)
cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:* 2026.2.0 (including) 2026.2.1 (excluding)
cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools