CVE-2025-3902
Block Class - Moderately critical - Cross Site Scripting - SA-CONTRIB-2025-043
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Block Class - Moderately critical - Cross Site Scripting - SA-CONTRIB-2025-043
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
- Record
CVE-2025-3902- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2025-12162
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
- Record
EUVD-2025-12162- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-v484-6wmj-xwfq
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')...
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
- Record
GHSA-v484-6wmj-xwfq- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
- Record
CVE-2025-3902- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Block Class - Moderately critical - Cross Site Scripting - SA-CONTRIB-2025-043
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Drupal Block Class allows Cross-Site Scripting (XSS).This issue affects Block Class: from 4.0.0 before 4.0.1.
- Record
CVE-2025-3902- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVDRUPAL-CONTRIB-2025-043 No score
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".
- Record
DRUPAL-CONTRIB-2025-043- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
drupal/block_classPackagist:https://packages.drupal.org/8 |
4.0.0 up to 4.0.1 | 4.0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-3902 is a medium vulnerability (CVSS 6.1) in Drupal Block Class, published April 23, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.25%, the 16th percentile. Fixed in drupal/block_class 4.0.1.