CVE-2025-3603: Privilege Escalation Vulnerability in Flynax Bridge Plugin for WordPress

Overview

The vulnerability we’re discussing today, CVE-2025-3603, is a significant risk to any organization using the Flynax Bridge plugin for WordPress, specifically versions up to and including 2.2.0. It’s a privilege escalation vulnerability that allows potential hackers to take over user accounts, even those of administrators. This vulnerability matters because it can lead to severe consequences like unauthorized access to sensitive data, system compromise, and possible data leakage, which could cause serious reputational damage and financial loss.

Vulnerability Summary

CVE ID: CVE-2025-3603
Severity: Critical (9.8/10)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: System compromise, data leakage

Affected Products

Product | Affected Versions

Flynax Bridge Plugin for WordPress | All versions up to and including 2.2.0

How the Exploit Works

The crux of this exploit lies in the plugin’s flawed identity validation process. When a user attempts to update their account details, including their password, the plugin does not properly verify the user’s identity. This flaw allows an attacker, even without authentication, to change any user’s password, including administrators’ passwords. Once the password is changed, the attacker can then use these new credentials to gain access to the user’s account, compromising the system, and potentially leading to data leakage.

Conceptual Example Code

Here, we provide a conceptual example of how an attacker might exploit this vulnerability, essentially by sending a POST request with the malicious payload to the vulnerable endpoint:

POST /wp-json/flynax/v1/updateUser HTTP/1.1
Host: target.example.com
Content-Type: application/json
{
"username": "admin",
"new_password": "attacker_password"
}

In this example, the attacker attempts to change the password of the “admin” account to “attacker_password”. If successful, the attacker would then have full administrative access to the WordPress site.

Mitigation

To mitigate this vulnerability, users should apply the vendor-provided patch immediately. If you can’t apply the patch right away, consider using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as a temporary mitigation strategy. However, these options only lower the risk and cannot fully eliminate it. The only complete solution is to update the Flynax Bridge plugin for WordPress to a patched version.