CVE-2024-39403: Adobe Commerce Stored XSS Vulnerability

CVE-2024-39403 Overview

CVE-2024-39403 is a stored Cross-Site Scripting (XSS) vulnerability affecting Adobe Commerce and Magento Open Source. A low-privileged authenticated attacker can inject malicious JavaScript into vulnerable form fields. The payload executes in a victim's browser when they render the page containing the injected content. Adobe classifies the vulnerability under [CWE-79] with high confidentiality impact due to potential exfiltration of sensitive session data. Affected versions include Adobe Commerce 2.4.7-p1, 2.4.6-p6, 2.4.5-p8, 2.4.4-p9, and earlier releases.

Critical Impact

Authenticated attackers can persist malicious JavaScript in Commerce form fields, leading to session theft, credential harvesting, and administrative account compromise when victims view affected pages.

Affected Products

• Adobe Commerce 2.4.7-p1 and earlier
• Adobe Commerce 2.4.6-p6, 2.4.5-p8, 2.4.4-p9 and earlier patch branches
• Magento Open Source (equivalent versions)

Discovery Timeline

• 2024-08-14 - CVE-2024-39403 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-39403

Vulnerability Analysis

The flaw is a stored XSS issue in Adobe Commerce and Magento Open Source form field handling. The application accepts user-supplied input into specific form fields without sufficient output encoding or input sanitization. The malicious payload persists in the backend datastore and is later rendered to other users' browsers in an executable context.

Because exploitation requires authentication as a low-privileged user and user interaction from a victim, the attack chain typically targets administrative or staff users who browse content-management pages. Successful execution runs attacker-controlled JavaScript inside the trusted origin of the Commerce storefront or admin interface. This scope change enables theft of session cookies, CSRF token exfiltration, and abuse of authenticated administrative APIs.

Root Cause

The root cause is improper neutralization of input during web page generation, classified as [CWE-79]. Vulnerable form fields fail to encode HTML control characters (<, >, ", ') before rendering stored values in the response. The application places attacker-controlled strings into HTML contexts where a script-execution sink can be reached.

Attack Vector

The attack requires network access to the Commerce application and a valid low-privileged account. The attacker submits a crafted payload through the vulnerable form field, which is persisted server-side. When a victim, typically an administrator, loads the page that renders the stored value, the browser executes the injected script under the site's origin. See the Adobe Magento Security Advisory APSB24-61 for vendor-provided technical context.

No verified public exploit code is available. The vulnerability is described in prose only per Adobe's advisory.

Detection Methods for CVE-2024-39403

Indicators of Compromise

• Stored records in Commerce form-backed tables containing HTML tag characters, javascript: URIs, or event-handler attributes such as onerror=, onload=, or onfocus=.
• Admin session activity originating from unexpected IP addresses or user agents shortly after an admin user viewed a page containing user-submitted content.
• Outbound HTTP requests from admin browsers to unknown domains carrying cookie or token values in query strings.

Detection Strategies

• Inspect application logs and database records for stored values containing <script, onerror, onload, or encoded variants such as <script.
• Correlate low-privileged account form submissions with subsequent admin page views to identify potential victim exposure.
• Deploy Content Security Policy (CSP) violation reporting to surface unexpected inline-script execution in Commerce admin pages.

Monitoring Recommendations

• Monitor Magento admin authentication events for anomalous session reuse, geographic drift, or privilege escalation following content review activity.
• Alert on modifications to admin users, integration tokens, or webhook configurations that follow a form submission by a low-privileged account.
• Ingest web server and application logs into a centralized data lake to enable retrospective hunting for XSS payload patterns across historical form submissions.

How to Mitigate CVE-2024-39403

Immediate Actions Required

• Apply the Adobe security update referenced in APSB24-61 to all Adobe Commerce and Magento Open Source instances.
• Audit low-privileged accounts and revoke unused or dormant credentials that could be leveraged to inject stored payloads.
• Review form-backed database tables for suspicious stored content and sanitize or remove identified payloads.

Patch Information

Adobe released fixed builds in security bulletin APSB24-61. Administrators should upgrade to Adobe Commerce 2.4.7-p2, 2.4.6-p7, 2.4.5-p9, 2.4.4-p10, or later, along with equivalent Magento Open Source releases. Refer to the Adobe Magento Security Advisory for exact build numbers and download instructions.

Workarounds

• Enforce a strict Content Security Policy that blocks inline scripts and restricts script sources to trusted origins.
• Restrict access to admin interfaces via IP allow-listing, VPN, or reverse-proxy authentication until patching is complete.
• Require multi-factor authentication for all administrative and content-editing accounts to reduce impact of session theft.

# Example CSP header to reduce stored XSS impact on Nginx fronting Magento
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self'; report-uri /csp-report" always;