CVE-2026-4327: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-fmwg-rf74-rjqj
CVSS 8.8
CWE-94
Published
Advisory Summary

CVE-2026-4327 is a HIGH (CVSS 8.8) security vulnerability vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-4327 at a Glance

CVE Identifier CVE-2026-4327
GHSA Identifier GHSA-fmwg-rf74-rjqj
Severity HIGH
CVSS v3.1 Base Score 8.8
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-4327

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-4327, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

The The Welcomizer plugin for WordPress is vulnerable to Remote Code Execution in all versions up to and including 2.8.1. This is due to missing authorization checks on the twiz_ajax_callback AJAX action's 'savesection' handler combined with the use of eval() to execute user-supplied 'custom logic' code on the frontend. The AJAX handler at twiz-ajax.php verifies a nonce but performs no current_user_can() capability check for the ACTION_SAVE_SECTION case. Furthermore, the nonce is exposed to any authenticated user through the directly-accessible twiz-ajax.js.php file which loads WordPress and outputs the nonce. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary PHP code via the twiz_custom_logic POST parameter when saving a section with output choice 'twiz_logic_output'.

References

NVD — CVE-2026-4327 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-4327
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.menu.class.php#L265
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.menu.class.php#L507
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.menu.class.php#L580
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.output.class.php#L828
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/twiz-ajax.php#L148
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L265
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L507
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L580
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.output.class.php#L828
plugins.trac.wordpress.org/browser/the-welcomi... WEB
https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/twiz-ajax.php#L148
plugins.trac.wordpress.org/log/the-welcomizer WEB
https://plugins.trac.wordpress.org/log/the-welcomizer
www.wordfence.com/threat-intel/vulner... WEB
https://www.wordfence.com/threat-intel/vulnerabilities/id/73fb7102-66ff-4309-a98f-bbbfd3ddbba6?source=cve

Frequently Asked Questions

What is CVE-2026-4327?
CVE-2026-4327 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-4327?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-4327?
CVE-2026-4327 has a CVSS v3.1 base score of 8.8 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-4327?
CVE-2026-4327 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Maven dependencies for CVE-2026-4327?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-fmwg-rf74-rjqj",
  "modified" : "2026-09-19T09:32:11Z",
  "published" : "2026-09-19T09:32:11Z",
  "aliases" : [ "CVE-2026-4327" ],
  "details" : "The The Welcomizer plugin for WordPress is vulnerable to Remote Code Execution in all versions up to and including 2.8.1. This is due to missing authorization checks on the twiz_ajax_callback AJAX action's 'savesection' handler combined with the use of eval() to execute user-supplied 'custom logic' code on the frontend. The AJAX handler at twiz-ajax.php verifies a nonce but performs no current_user_can() capability check for the ACTION_SAVE_SECTION case. Furthermore, the nonce is exposed to any authenticated user through the directly-accessible twiz-ajax.js.php file which loads WordPress and outputs the nonce. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject arbitrary PHP code via the twiz_custom_logic POST parameter when saving a section with output choice 'twiz_logic_output'.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
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  }, {
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  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.menu.class.php#L507"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.menu.class.php#L580"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/includes/twiz.output.class.php#L828"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/tags/2.8.1/twiz-ajax.php#L148"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L265"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L507"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.menu.class.php#L580"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/includes/twiz.output.class.php#L828"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/browser/the-welcomizer/trunk/twiz-ajax.php#L148"
  }, {
    "type" : "WEB",
    "url" : "https://plugins.trac.wordpress.org/log/the-welcomizer"
  }, {
    "type" : "WEB",
    "url" : "https://www.wordfence.com/threat-intel/vulnerabilities/id/73fb7102-66ff-4309-a98f-bbbfd3ddbba6?source=cve"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-19T08:16:53Z"
  }
}