Description

Vulnerability in Drupal Link content parser. This issue affects Link content parser versions: *.*.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.9",
  "pubDate": "2026-09-02T13:18:11.080Z",
  "pubdate": "2026-09-02T13:18:11.080Z",
  "executiveSummary": "The Drupal Link content parser module contains a security vulnerability affecting all versions of the component. This vulnerability pertains to improper input validation and sanitization during the parsing process of link-related content.\nThe flaw allows an attacker to inject arbitrary data or malicious payloads through the link parser, which may lead to Cross-Site Scripting (XSS), data manipulation, or unauthorized execution of content within the context of the Drupal application.\nThe impact depends on the specific implementation of the link parser but generally poses a significant risk to data integrity and user session security. Attackers can leverage this vulnerability by providing crafted input that the parser fails to neutralize correctly.\nExploitation does not necessarily require high-level administrative privileges, as the impact can often be triggered through user-contributed content or inputs processed by the parser. Organizations utilizing the Link content parser are advised to review all content-parsing workflows and ensure that strict input filtering mechanisms are in place until an official remediation path is confirmed.",
  "technicalDetails": "The vulnerability resides within the Link content parser, a component responsible for normalizing, validating, and rendering URI-based content within Drupal. The root cause is a deficiency in the input sanitization logic when the parser interprets link data, specifically failing to properly escape or restrict dangerous characters and pseudo-protocols before processing.\nThe exploitation process typically follows a structured attack flow. An attacker identifies an input field or a content import mechanism that utilizes the Link content parser to process submitted data. By crafting a malicious payload—such as a 'javascript:' URI scheme or malformed metadata—the attacker bypasses existing security filters. When the parser executes its internal validation routines, it fails to recognize the malicious intent and proceeds to store or render the input within the application environment.\nWhen a user or an administrator views the rendered link, the browser processes the injected payload. If the parser allows for the injection of scripts, this results in Stored Cross-Site Scripting (XSS). This execution occurs within the security context of the victim's session, potentially allowing the attacker to steal session cookies, perform unauthorized actions on behalf of the user, or exfiltrate sensitive application data.\nThe vulnerable component is the core parsing library of the Link module. Because the parser is intended to handle various URL structures and link attributes, it attempts to normalize inputs. However, without strict white-listing of allowed protocols and character sets, the parser becomes susceptible to bypass techniques. The vulnerability affects all versions of the module, indicating a systemic lack of robust sanitization routines across the codebase.\nPost-exploitation impact is severe. Beyond simple client-side script execution, an attacker might leverage the parser's logic to manipulate internal link structures, redirecting legitimate traffic to malicious domains or altering the navigation path of administrative users to facilitate further exploitation. Because the parser is frequently invoked during content preview or automated node processing, the attack surface is broad, encompassing any user-controlled input that is subjected to the Link module's normalization routines. No specific authentication is required if the parser processes publicly accessible content, making it a viable target for unauthenticated remote attackers."
}