CVE-2026-9189: Software Security Vulnerability Vulnerability
MODERATECVE-2026-9189 is a MODERATE (CVSS 5.3) security vulnerability vulnerability (CWE-345: Insufficient Verification of Data Authenticity) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.. Remediation is available in the latest vendor maintenance releases.
CVE-2026-9189 at a Glance
Security Impact
CVSS: 5.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).
How to Fix CVE-2026-9189
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.
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:treeHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-9189, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:treeAnalyze 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-345: Insufficient Verification of Data Authenticity, where the product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. 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
References
Frequently Asked Questions
What is CVE-2026-9189?
Which Software versions are affected?
What version fixes CVE-2026-9189?
What is the CVSS score of CVE-2026-9189?
What CWE is associated with CVE-2026-9189?
How can I check Maven dependencies for CVE-2026-9189?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-vr4h-g9wj-2p4g",
"modified" : "2026-05-29T09:31:07Z",
"published" : "2026-05-29T09:31:07Z",
"aliases" : [ "CVE-2026-9189" ],
"details" : "The Contact Form 7 – PayPal & Stripe Add-on plugin for WordPress is vulnerable to Payment Bypass via Insufficient Verification of Data Authenticity in all versions up to, and including, 2.4.9. Although `cf7pp_paypal_ipn_handler()` correctly validates IPN authenticity by posting back to PayPal with `cmd=_notify-validate`, it fails to compare the IPN payload's `mc_gross` (payment amount), `mc_currency`, or `receiver_email` fields against the corresponding stored order values before passing the attacker-controlled `invoice` field directly to `cf7pp_complete_payment()`, which marks the order completed after only an integer cast with no amount verification. This makes it possible for unauthenticated attackers to mark arbitrary high-value pending orders as fully paid by making a minimal real PayPal payment and crafting an IPN whose `invoice` parameter references the targeted order, effectively completing purchases without tendering the required payment amount.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-9189"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/functions.php#L31"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L106"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.6/includes/payments/paypal_handler.php#L75"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/functions.php#L31"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L106"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/contact-form-7-paypal-add-on/tags/2.4.8/includes/payments/paypal_handler.php#L75"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/changeset/3551197/contact-form-7-paypal-add-on"
}, {
"type" : "WEB",
"url" : "https://www.wordfence.com/threat-intel/vulnerabilities/id/5e274781-1c20-4224-bc10-26dadb9b1e07?source=cve"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-345" ],
"severity" : "MODERATE",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-05-29T09:16:18Z"
}
}