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Date:
2025-April-23
Security risk:
Vulnerability:
Cross Site Scripting
Affected versions:
>=4.0.0 <4.0.1
CVE IDs:
CVE-2025-3902
Description:
Block Class enables you to add custom attributes to blocks.
The module did not sufficiently sanitize custom attribute input, allowing for potential XSS attacks when malicious JavaScript was injected as a custom attribute.
This vulnerability is mitigated by the fact that an attacker must have a role with the permission "administer block classes".
Solution:
Install the latest version:
- If you use the Block Class on 4.0.x upgrade to Block Class 4.0.1
Reported By:
- Ivo Van Geertruyen (mr.baileys) of the Drupal Security Team
Fixed By:
Coordinated By:
- Greg Knaddison (greggles) of the Drupal Security Team
- Juraj Nemec (poker10) of the Drupal Security Team
