CVE-2026-114534 in Block Attributes Plugin
Summary
by MITRE • 10/30/2026
Improper Neutralization of Input During Web Page Generation ("Cross-site Scripting") vulnerability in Drupal Block Attributes allows Stored XSS. This issue affects Block Attributes versions: from 0.0.0 to 2.1.0.
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Analysis
by VulDB Data Team • 10/30/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability is located within the Block Attributes module for Drupal, affecting all versions from 0.0.0 through 2.1.0. The core technical issue stems from insufficient validation and sanitization of user-supplied input when it is processed to generate HTML output. In a typical web application architecture, data entered by users or administrators is often stored in a database and later retrieved for display on web pages. When the Block Attributes module processes these inputs without adequately stripping out malicious script tags or encoding special characters, it allows attackers to inject client-side scripts into the page content served to other users. This failure to neutralize dangerous input vectors creates an opening for persistent data manipulation within the application context.
From a technical perspective, this is classified as a Stored XSS vulnerability because the malicious payload is saved on the target server, typically in the database associated with block configurations or attributes. Unlike reflected XSS where the attack script is immediately executed via a crafted URL, stored XSS persists until an administrator or another user views the affected page. When a victim loads the compromised web page containing the injected JavaScript code, the browser executes this script within the context of the Drupal site. This execution environment grants the attacker significant privileges relative to the session of the viewing user. The vulnerability exploits the trust that users have in the website and its content, allowing an adversary to bypass standard security controls such as the same-origin policy because the malicious script originates from a trusted domain.
The operational impact of this vulnerability is severe due to its persistent nature and potential for widespread exploitation. An attacker who successfully exploits this flaw can perform a variety of malicious actions depending on their level of access within Drupal. If an authenticated user with permission to configure blocks can inject the payload, they effectively compromise all users who view those pages. Common consequences include session hijacking, where the attacker steals authentication cookies or tokens to impersonate legitimate users and gain unauthorized administrative access. Additionally, attackers can deface websites by altering displayed content, redirect users to malicious phishing sites designed to steal credentials, or deploy keyloggers to capture sensitive information entered on the site. The persistence of the attack means that even after the initial injection is discovered, it continues to affect new visitors until the vulnerable code is explicitly removed from the database and patched in the application logic.
This vulnerability maps directly to CWE-79, which defines Improper Neutralization of Input During Web Page Generation: Cross-site Scripting, highlighting the failure to sanitize user input before rendering it as HTML. In terms of offensive security frameworks, this aligns with MITRE ATT&CK technique T1059, specifically sub-technique 007 for Command and Scripting Interpretation via JavaScript. The attack vector typically involves an attacker crafting a malicious payload containing script tags or event handlers such onerror or onload, which are then embedded into block attributes through the Drupal administrative interface or API endpoints exposed by the module. Because the vulnerability exists in versions as old as 0.0.0 and persists up to 2.1.0, it indicates a long-standing lack of input validation rigor within this specific component's codebase.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary recommendation is to upgrade the Block Attributes module to version 2.1.1 or later, where developers have presumably implemented proper output encoding functions such as Drupal’s check_plain() or HTML entity encoding routines that convert special characters like < > & " ' into their safe equivalents before rendering. For organizations unable to immediately patch due to compatibility constraints, implementing a Web Application Firewall with rules specifically tuned to detect and block XSS payloads in POST requests targeting block configuration endpoints can provide temporary protection. Furthermore, enforcing strict Content Security Policy headers on the Drupal site can mitigate the impact of any successful injection by restricting the sources from which scripts are allowed to execute, thereby preventing unauthorized inline script execution even if an attacker manages to inject code into the DOM. Regular security audits and static analysis tools should be employed during development cycles to ensure that all user inputs undergo rigorous sanitization before being stored or displayed.