CVE-2025-3902Network attack vector

Stored XSS via unsanitized custom attributes

Published Apr 23, 2025 · Updated Apr 23, 2025

Cross-site scripting in Drupal Block Class 4.0.0 allows remote authenticated users to execute JavaScript through malicious block attributes. The module stores custom attribute input without sufficient sanitization and renders attacker-supplied JavaScript in block markup. Exploitation requires the administer block classes permission and affects users who view a page containing the modified block.

CVSS severity6.1
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Drupal Block Class 4.0.0 allows remote authenticated users to execute JavaScript through malicious block attributes. The module stores custom attribute input without sufficient sanitization and renders attacker-supplied JavaScript in block markup. Exploitation requires the administer block classes permission and affects users who view a page containing the modified block.

The record

CVE
CVE-2025-3902
Published
Apr 23, 2025
Updated
Apr 23, 2025
Vendor
OAuth.js
Product
Block Class
Classifications
CWE-79, CAPEC-63, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 <4.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OAuth.js · Block Classversion=4.0.0 <4.0.1

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-63Cross-Site Scripting (XSS)
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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