CVE-2026-27265: Adobe Experience Manager XSS Vulnerability

CVE-2026-27265 Overview

Adobe Experience Manager versions 6.5.23 and earlier are affected by a stored Cross-Site Scripting (XSS) vulnerability that could be abused by a low-privileged attacker to inject malicious scripts into vulnerable form fields. Malicious JavaScript may be executed in a victim's browser when they browse to the page containing the vulnerable field.

Critical Impact

A low-privileged attacker can inject persistent malicious scripts into form fields, enabling session hijacking, credential theft, or malicious redirects when victims view affected pages.

Affected Products

• Adobe Experience Manager versions 6.5.23 and earlier
• Adobe Experience Manager 6.5 LTS (all service packs)
• Adobe Experience Manager AEM Cloud Service (prior to patch)

Discovery Timeline

• 2026-03-11 - CVE-2026-27265 published to NVD
• 2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-27265

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting (XSS). The stored variant of this vulnerability is particularly dangerous because the malicious payload persists in the application's database or storage, affecting all users who subsequently view the compromised content.

Adobe Experience Manager (AEM) is an enterprise content management system widely used for building websites, mobile apps, and forms. The vulnerability exists in form field handling where user-supplied input is not properly sanitized before being stored and later rendered to other users. This allows attackers with low-privilege access (such as content contributors) to inject JavaScript code that executes in the context of other users' sessions.

The attack requires user interaction—a victim must navigate to the page containing the malicious payload. Upon rendering the vulnerable field, the browser executes the injected script with the victim's session context, potentially allowing the attacker to steal session cookies, perform actions on behalf of the victim, or redirect users to malicious sites.

Root Cause

The root cause of this vulnerability is insufficient input validation and output encoding in Adobe Experience Manager's form field processing logic. When user-controlled data is stored and subsequently rendered in web pages without proper sanitization, it creates an opportunity for script injection. The application fails to properly escape or encode special HTML characters before rendering stored content, allowing injected script tags or event handlers to execute in the browser.

Attack Vector

The attack vector is network-based and requires low privileges to execute. An attacker must first authenticate to the Adobe Experience Manager instance with at least minimal content creation privileges. They then identify vulnerable form fields that accept and store user input without proper sanitization.

The attacker crafts a malicious payload containing JavaScript code and submits it through a vulnerable form field. This payload is stored in the AEM content repository. When legitimate users—including administrators or other privileged users—browse to pages that render the compromised field, the malicious script executes in their browser session.

The scope is changed, meaning the vulnerability can affect resources beyond the vulnerable component, such as the user's browser session or other web applications sharing the same origin context.

Detection Methods for CVE-2026-27265

Indicators of Compromise

• Unexpected JavaScript code or <script> tags appearing in AEM form field content
• Unusual content modifications by low-privileged users in AEM author logs
• Reports of browser redirects, pop-ups, or unexpected behavior when viewing specific AEM pages
• Session hijacking incidents or unauthorized actions traced back to specific content pages

Detection Strategies

• Review AEM audit logs for suspicious content modifications, particularly in form fields and user-generated content areas
• Implement Web Application Firewall (WAF) rules to detect common XSS patterns in requests to AEM authoring interfaces
• Deploy content scanning tools to identify stored payloads containing script tags, event handlers, or JavaScript URIs
• Monitor for anomalous session activity that could indicate session hijacking following XSS exploitation

Monitoring Recommendations

• Enable and centralize AEM replication and audit logs for security review
• Configure Content Security Policy (CSP) headers to restrict inline script execution and report violations
• Implement real-time alerting for content containing suspicious HTML/JavaScript patterns
• Conduct periodic security scans of AEM content repositories for XSS payloads

How to Mitigate CVE-2026-27265

Immediate Actions Required

• Apply the security update referenced in Adobe Security Advisory APSB26-24 immediately
• Audit existing AEM content for potentially malicious scripts in form fields
• Review access privileges and restrict content authoring permissions to trusted users
• Implement Content Security Policy (CSP) headers as an additional defense layer

Patch Information

Adobe has released a security patch addressing this vulnerability. Organizations should upgrade Adobe Experience Manager to the latest available version that includes the fix. Detailed patch information and download instructions are available in the Adobe Security Advisory APSB26-24.

For AEM Cloud Service customers, Adobe applies security updates automatically. On-premise customers running AEM 6.5 should apply the latest cumulative fix pack or service pack that addresses this vulnerability.

Workarounds

• Restrict content authoring permissions to only trusted users who require them
• Implement strict input validation at the application level for all form fields accepting user content
• Deploy a Web Application Firewall (WAF) with XSS detection rules in front of AEM instances
• Enable and enforce Content Security Policy (CSP) headers to mitigate the impact of any successful XSS injection

# Example: Content Security Policy header configuration for Apache
# Add to AEM Dispatcher or web server configuration
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"