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Essential BlocksWordPress extension · Wpdeveloper

CVE-2024-13803

MEDIUM · 5.4 CVSS v3.1 Published 2025-02-26
Fix available
A fix is available. Upgrade to after 5.2.3 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The Essential Blocks – Page Builder Gutenberg Blocks, Patterns & Templates plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘data-marker’ parameter in all versions up to, and including, 5.2.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Essential Blocks plugin for WordPress versions up to 5.2.3 contains a stored Cross-Site Scripting vulnerability in the 'data-marker' parameter. Authenticated attackers with Contributor-level access can inject arbitrary JavaScript because the plugin fails to properly sanitize input and escape output, causing malicious scripts to execute when users view compromised pages.

MitigationUpdate the Essential Blocks plugin to version 5.2.4 or later which patches this vulnerability. Until then, restrict Contributor-level user permissions and review existing pages for malicious 'data-marker' attribute values.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Essential BlocksWordPress extension
Affected:<= 5.2.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Essential Blocks plugin installation and version
    In WordPress admin, go to Plugins > Installed Plugins and locate 'Essential Blocks' under the Wpdeveloper entry. Note the version number displayed. Alternatively, check the plugin file /wp-content/plugins/essential-blocks/readme.txt for the 'Stable tag' entry.
    Affected if The installed version is 5.2.3 or lower.
  2. Identify content using the data-marker attribute
    Search the WordPress database for posts containing 'data-marker' by querying the wp_posts table: SELECT ID, post_title, post_type FROM wp_posts WHERE post_content LIKE '%data-marker%' AND post_status IN ('publish', 'draft', 'pending').
    Affected if Any posts, pages, or custom post types contain the data-marker attribute in their content.
  3. Inspect stored data-marker values for malicious payloads
    Extract the raw post content containing data-marker and examine the attribute values. Query: SELECT ID, post_content FROM wp_posts WHERE post_content LIKE '%data-marker%'. Manually review the data-marker attribute values for unescaped characters like <, >, ', or javascript: that may indicate XSS injection.
    Affected if The data-marker attribute contains unescaped HTML, JavaScript code, or suspicious URI schemes.
  4. Review contributor-level user accounts
    Check WordPress users with Contributor role: Go to Users > All Users in admin, or query SELECT user_login, user_email FROM wp_users WHERE ID IN (SELECT user_id FROM wp_usermeta WHERE meta_key = 'wp_capabilities' AND meta_value LIKE '%contributor%').
    Affected if There are active Contributor-level user accounts that could potentially exploit this vulnerability.

You are affected if Essential Blocks version 5.2.3 or lower is installed AND any content contains the data-marker attribute with unsanitized values.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 5.2.3
Interim mitigation

Update the Essential Blocks plugin to version 5.2.4 or later which patches this vulnerability. Until then, restrict Contributor-level user permissions and review existing pages for malicious 'data-marker' attribute values.

Fix this in Essential Blocks Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-13803 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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