Otter Blocks Vulnerability – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE – Authenticated (Contributor+) Stored Cross-Site Scripting – CVE-2024-2841 | WordPress Plugin Vulnerability Report

Plugin Name: Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE

Key Information:

  • Software Type: Plugin
  • Software Slug: otter-blocks
  • Software Status: Active
  • Software Author: themeisle
  • Software Downloads: 7,072,421
  • Active Installs: 300,000
  • Last Updated: April 1, 2024
  • Patched Versions: 2.6.6
  • Affected Versions: <= 2.6.5

Vulnerability Details:

  • Name: Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE <= 2.6.5
  • Title: Authenticated (Contributor+) Stored Cross-Site Scripting
  • Type: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
  • CVE: CVE-2024-2841
  • CVSS Score: 6.4
  • Publicly Published: March 28, 2024
  • Researcher: Ngô Thiên An (ancorn_) - VNPT-VCI
  • Description: The Otter Blocks plugin, a popular tool for enhancing Gutenberg editor functionality, is vulnerable to Stored Cross-Site Scripting in versions up to and including 2.6.5. The vulnerability stems from insufficient sanitization and escaping of user-supplied attributes such as 'id' within the plugin's widgets. This flaw allows authenticated users with contributor-level permissions to execute arbitrary web scripts on pages, posing significant security risks.


The Otter Blocks plugin, integral to over 300,000 WordPress sites, has been identified to harbor a Stored Cross-Site Scripting vulnerability in versions up to 2.6.5. This security risk, which could allow malicious scripts to be executed, has been effectively addressed in version 2.6.6.

Detailed Overview:

Discovered by researcher Ngô Thiên An, this vulnerability underscores the critical need for robust input validation within plugins. Stored Cross-Site Scripting vulnerabilities like this one can lead to unauthorized access, data breaches, and compromised user sessions. The prompt issuance of a patched version (2.6.6) by the Otter Blocks development team mitigates the vulnerability, safeguarding websites against potential exploits.

Advice for Users:

  • Immediate Action: Users of the Otter Blocks plugin must update to version 2.6.6 immediately to protect their sites from potential exploitation.
  • Check for Signs of Vulnerability: Administrators should review their websites for any unusual or unauthorized content that could indicate the vulnerability has been exploited.
  • Alternate Plugins: While the vulnerability has been patched, users may consider evaluating alternative plugins that provide similar functionality, especially if ongoing security concerns arise.
  • Stay Updated: Regularly updating all WordPress plugins is essential for maintaining site security. Users should monitor for updates and apply them promptly to defend against known vulnerabilities.


The swift action taken by the Otter Blocks development team to address the Stored Cross-Site Scripting vulnerability highlights the importance of continuous vigilance and timely updates in the realm of website security. Users are urged to ensure their installations are updated to version 2.6.6 or later to maintain the integrity and security of their WordPress sites.


Detailed Report: 

In the digital expanse where creativity meets functionality, WordPress plugins stand as pivotal tools in sculpting the web's vast landscape. Among these, Otter Blocks – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE, emerges as a cornerstone for over 300,000 websites, embodying the spirit of innovation and ease of use. However, the recent discovery of a Stored Cross-Site Scripting (XSS) vulnerability, dubbed CVE-2024-2841, casts a shadow over its utility, reminding us of the imperatives of vigilance and timely updates in the realm of digital security.

About Otter Blocks:

Otter Blocks enriches the WordPress Gutenberg editor with enhanced functionality, allowing users to effortlessly craft and customize their sites. Developed by themeisle, this plugin has seen over 7 million downloads, a testament to its popularity and integral role in the WordPress ecosystem. Despite its acclaim, Otter Blocks was not immune to vulnerabilities, with the latest patch released in version 2.6.6 addressing a critical flaw.

The Vulnerability at Hand:

CVE-2024-2841 exposes Otter Blocks to Stored Cross-Site Scripting attacks through insufficiently sanitized user inputs, particularly in the plugin's widgets. This vulnerability, prevalent in versions up to 2.6.5, could allow attackers with contributor-level access to inject malicious scripts, compromising site integrity and user security. This discovery, credited to researcher Ngô Thiên An of VNPT-VCI, underscores the complex interplay between functionality and security.

Risks and Impacts:

The implications of such a vulnerability are far-reaching, potentially affecting data confidentiality, integrity, and the overall trustworthiness of impacted sites. Unauthorized access, data breaches, and the manipulation of site content are among the tangible threats posed by CVE-2024-2841, highlighting the paramount importance of robust security measures.

Remediation and Precaution:

In response, themeisle swiftly released Otter Blocks version 2.6.6, effectively neutralizing the vulnerability. Users are urged to update immediately, ensuring their sites are safeguarded against potential exploitation. Additionally, regular monitoring for unusual site activity and exploring alternative plugins can serve as prudent measures in bolstering site security.

Historical Context:

This is not Otter Blocks' first encounter with vulnerability; three previous instances since May 2, 2023, have been documented. This history not only emphasizes the inevitability of digital vulnerabilities but also highlights the responsive measures taken by developers to maintain user trust and security.

The Imperative of Digital Vigilance:

For small business owners, the digital landscape offers boundless opportunities, albeit intertwined with the challenges of maintaining a secure online presence. The incident with Otter Blocks serves as a crucial reminder of the ongoing need for vigilance, regular updates, and a proactive stance towards digital security. In a world where digital threats loom large, the safety of your online domain hinges on the swiftness of your response to vulnerabilities and the depth of your commitment to regular maintenance.

In conclusion, navigating the digital realm demands more than just creativity and innovation; it calls for an unwavering dedication to security. For small business owners managing WordPress sites, staying abreast of updates and vulnerabilities is not just best practice—it's a critical defense against the ever-evolving landscape of cyber threats. Let the story of Otter Blocks be a reminder: in the digital age, vigilance is your strongest ally.

Staying Secure

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Don't tackle security risks alone. Let us help you assess any impact from this vulnerability, update your plugins, and implement ongoing maintenance to avoid future threats. We treat your website like it's our own - because we know how critical it is for reaching your customers.

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Otter Blocks Vulnerability – Gutenberg Blocks, Page Builder for Gutenberg Editor & FSE – Authenticated (Contributor+) Stored Cross-Site Scripting – CVE-2024-2841 | WordPress Plugin Vulnerability Report FAQs

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