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

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CVE-2026-32243

Severity CVSS v4.0:
MEDIUM
Type:
CWE-79 Cross-Site Scripting (XSS)
Publication date:
31/03/2026
Last modified:
09/04/2026

Description

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.3, 2026.2.0-latest to before 2026.2.2, and 2026.3.0-latest to before 2026.3.0, an attacker with the ability to create shared AI conversations could inject arbitrary HTML and JavaScript via crafted conversation titles. This payload would execute in the browser of any user viewing the onebox preview, potentially allowing session hijacking or unauthorized actions on behalf of the victim. This issue has been patched in versions 2026.1.3, 2026.2.2, and 2026.3.0.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 5.30 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): Low
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
5.30
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.40 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/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): Low
Integrity (I): Low
Availability (A): None

Base Score 3.x
5.40
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:discourse:discourse:*:*:*:*:latest:*:*:* 2026.1.0 (including) 2026.1.3 (excluding)
cpe:2.3:a:discourse:discourse:*:*:*:*:latest:*:*:* 2026.2.0 (including) 2026.2.2 (excluding)
cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*
cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest.1:*:*:*

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


References to Advisories, Solutions, and Tools