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Essential BlocksWordPress extension · Wpdeveloper

CVE-2023-4386

HIGH · 8.1 CVSS v3.1 Published 2023-10-20
Fix available
A fix is available. Upgrade to after 4.2.0 or later.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 4.2.0 via deserialization of untrusted input in the get_posts function. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

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 WordPress plugin up to version 4.2.0 is vulnerable to PHP Object Injection through unsafe deserialization of untrusted input in the get_posts function. Unauthenticated attackers can inject arbitrary PHP objects, though no POP chain exists within the plugin itself. However, if other plugins or themes on the target system provide a POP chain, attackers could potentially achieve arbitrary file deletion, data retrieval, or code execution.

MitigationUpdate Essential Blocks plugin to a version beyond 4.2.0. Audit other installed plugins and themes for POP chain vulnerabilities that could be chained with this issue, and remove any unnecessary or vulnerable extensions.

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:<= 4.2.0

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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. Confirm Essential Blocks plugin is installed
    Navigate to WordPress admin Dashboard > Plugins > Installed Plugins, or check wp-content/plugins/essential-blocks/ directory exists on the server
    Affected if The plugin is present in the WordPress installation
  2. Identify the installed version of Essential Blocks
    In WordPress admin, go to Plugins > Installed Plugins and find the Essential Blocks entry to view the version number, or check the main plugin file (e.g., essential-blocks.php) for the 'Version' header
    Affected if Version is 4.2.0 or lower
  3. Check if the get_posts function is accessible
    Review plugin files (typically in includes/ or src/ folders) for the get_posts function that handles unserialize() on user-supplied input; check if the function is hooked to a publicly accessible AJAX action or REST endpoint
    Affected if The vulnerable get_posts function exists and is exposed to unauthenticated requests
  4. Audit other plugins for POP chain potential
    Review all other installed plugins and themes for known PHP object injection vulnerabilities or unserialize() usage that could form a POP chain; check plugin versions against known vulnerable plugins
    Affected if Other installed extensions contain exploitable POP chains that could be chained with this vulnerability

You are affected if Essential Blocks plugin version 4.2.0 or lower is installed AND the get_posts function is accessible to unauthenticated users AND other plugins on the site provide a usable POP chain for code execution.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 4.2.0
Interim mitigation

Update Essential Blocks plugin to a version beyond 4.2.0. Audit other installed plugins and themes for POP chain vulnerabilities that could be chained with this issue, and remove any unnecessary or vulnerable extensions.

Recommended fix High confidence

Essential Blocks version 4.2.1 or latest stable release

  1. Navigate to the WordPress dashboard
  2. Go to Plugins > Installed Plugins
  3. Find Essential Blocks plugin
  4. Check if current version is 4.2.0 or lower
  5. If vulnerable, click 'Update Now' or manually update to the latest version (4.2.1 or higher)
  6. Verify the update completed successfully

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Essential Blocks Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

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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-2023-4386 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data