CVE-2026-23891

Severity CVSS v4.0:

CRITICAL

Type:

CWE-79 Cross-Site Scripting (XSS)

Publication date:

13/04/2026

Last modified:

22/04/2026

Description

Decidim is a participatory democracy framework. In versions below 0.30.5 and 0.31.0.rc1 through 0.31.0, a stored code execution vulnerability in the user name field allows a low-privileged attacker to execute arbitrary code in the context of any user who passively visits a comment page, resulting in high confidentiality and integrity impact across security boundaries. This issue has been fixed in versions 0.30.5 and 0.31.1.

Impact

Vector 4.0

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

Base Score: 9.30 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L

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

Base Score 4.0

9.30

Severity 4.0

CRITICAL

Vector 3.x

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

Base Score: 8.70 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

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

Base Score 3.x

8.70

Severity 3.x

HIGH

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:a:decidim:decidim::::::ruby::*		0.30.5 (excluding)
cpe:2.3:a:decidim:decidim::::::ruby::*	0.31.0 (including)	0.31.1 (excluding)

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

CVE-2026-23891

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools