Description

Contributor Cross Site Scripting (XSS) in Table Of Contents Block <= 1.5.0 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-08-18T15:16:59.300Z",
  "pubdate": "2026-08-18T15:16:59.300Z",
  "executiveSummary": "This security analysis details a Cross-Site Scripting (XSS) vulnerability affecting the Table Of Contents Block plugin, specifically targeting versions 1.5.0 and prior. The security flaw stems from improper input sanitization and output encoding within the contributor-level interface of the affected product, allowing low-privileged authenticated users to inject arbitrary client-side scripts, such as JavaScript or HTML, into the application context.\nThe primary impact of this vulnerability involves the execution of malicious scripts in the context of other users' browsers, including higher-privileged administrators. An attacker capable of contributing content can leverage this capability to hijack administrative sessions, steal sensitive session tokens, manipulate DOM elements, or perform unauthorized administrative actions on the target WordPress installation.\nThe risk implications are significant for multi-author environments where untrusted contributors have publishing or editing privileges. Exploitation requires authenticated access with contributor-level capabilities to create or modify vulnerable block parameters. Because the payload executes within the victim browser context upon rendering the table of contents block, no complex social engineering is required beyond standard content creation workflows.",
  "technicalDetails": "The vulnerability is classified as a Cross-Site Scripting (XSS) flaw localized within the Table Of Contents Block plugin versions <= 1.5.0. The root cause of the issue resides in the insufficient validation and sanitization of user-supplied data handled by the block's attributes, coupled with a lack of proper contextual output encoding when the stored block data is rendered on the frontend or backend interface.\nSpecifically, the vulnerable component fails to adequately strip or neutralize executable markup within parameters processed by the block rendering functions. When a user with contributor-level privileges crafts a specially formulated payload inside the block configurations, the malicious input is persisted into the database without adequate filtering. Upon subsequent rendering of the Table Of Contents Block, the raw payload is reflected directly into the Document Object Model (DOM).\nThe attack flow proceeds as follows: First, the authenticated attacker with contributor privileges crafts a new post or edits an existing one, inserting the malicious XSS payload into the attributes processed by the Table Of Contents Block. Second, the application saves the malicious post content containing the unsanitized payload into the backend database. Third, a higher-privileged user, such as an administrator or editor, views the rendered page containing the affected block. Fourth, the browser of the victim processes the HTML response, executing the injected script within the security context of the victim's session.\nThe post-exploitation impact includes session hijacking via the theft of cookies or authentication tokens, unauthorized modification of site content, creation of rogue administrator accounts, and pivoting to other components within the content management system. Network exposure is contingent upon web accessibility to the target application instance, and authentication is strictly required at the contributor privilege level to inject the initial payload."
}