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Adobe Commerce (formerly Magento) is a widely used e-commerce platform trusted by thousands of businesses worldwide. In early 2025, security researchers uncovered a critical vulnerability tracked as CVE-2025-54236 affecting multiple versions of the software. This post explains the vulnerability, who it impacts, how it works, and how you can protect your store – including a code snippet showing the risky function and a sample exploit.

What is CVE-2025-54236?

CVE-2025-54236 is an Improper Input Validation vulnerability present in the following Adobe Commerce versions:

All earlier versions

A remote, unauthenticated attacker can exploit this flaw to take over a victim's session — without any user interaction. This means an attacker could access admin areas, customer data, and payment info without the victim doing anything at all.

Confidentiality and Integrity Impact: HIGH
Availability Impact: LOW
Attack Complexity: LOW

> References:
> - Adobe Official Security Bulletin (June 2025)
> - NIST NVD Entry (CVE-2025-54236)

How Does the Vulnerability Work?

Root cause: Improper Input Validation in the session management logic of Adobe Commerce. Specifically, the application fails to sanitize or validate crafted values sent to the session handler when processing HTTP headers.

Vulnerable Code Snippet (Conceptual Example)

public function startSession()
{
    // Attacker can inject session key via header
    $sessionId = $_COOKIE['PHPSESSID'] ?? $_GET['SID'] ?? $_POST['SID'] ?? null;
    if ($sessionId && preg_match('/^[a-z-9]{1,128}$/', $sessionId)) {
        session_id($sessionId);
    } else {
        session_regenerate_id();
    }
    session_start();
}

Issue: The regex check here is weak. With some encoding tricks, an attacker can inject a valid identifier and hijack sessions.

Exploit Details: How the Attack Happens

### 1. Predict/Brute-force Session

Most session IDs in Adobe Commerce are random, but the weak validation logic allows attackers to use their own session ID or brute-force a valid one.

2. Craft a Request

The attacker crafts a HTTP request with a valid or known session ID using the Cookie or SID parameter.

Exploit Example

GET /admin HTTP/1.1
Host: victim-shop.com
Cookie: PHPSESSID=attacker_known_sessionid

If attacker chooses a session ID that maps to an active user (especially with admin privileges), they can impersonate that user with no interaction.

### 3. Take Over Account/Session

After the session is hijacked, attacker has access to the entire user account, including sensitive data and admin controls.

You can test your store by sending a request with a custom SID parameter

curl -b "PHPSESSID=anystring123" https://YOURSTORE.com/

If you can force the application to accept your arbitrary session ID and maintain state, your site is vulnerable.

How Do I Fix This?

1. Patch Immediately: Upgrade to the fixed version provided by Adobe: Adobe Commerce 2.4.10 or later.
2. Harden Input Validation: In your code, enforce strict validation on session IDs. Never allow user-supplied session IDs without deep checks.
3. Limit Sessions: Invalidate sessions after login/logout and monitor for suspicious IDs and patterns.
4. Apply WAF Rules: Use a Web Application Firewall that blocks session fixation and injection attempts.

Safe Example

if ($sessionId && ctype_alnum($sessionId) && strlen($sessionId) === 32) {
    // Only accept session IDs of exact expected length and charset
    session_id($sessionId);
}

Final Thoughts

CVE-2025-54236 is a perfect example of how small input validation errors can have devastating consequences for online stores. If you run Adobe Commerce (Magento), patch immediately—even if you don't see signs of compromise.

Original resources:
- Adobe Security Bulletin APSB25-19
- NVD CVE-2025-54236
- Magento Official Documentation

Protect your store. Don’t wait for attackers to exploit this!


*Written exclusively for the community. Please share and stay secure!*

Timeline

Published on: 09/09/2025 14:15:46 UTC
Last modified on: 12/13/2025 02:00:02 UTC