CVE-2026-27249: Adobe Experience Manager XSS Vulnerability

CVE-2026-27249 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
Low-privileged attackers can inject persistent malicious scripts that execute in victims' browsers, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of authenticated users.

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

Discovery Timeline

2026-03-11 - CVE-2026-27249 published to NVD
2026-03-11 - Last updated in NVD database

Technical Details for CVE-2026-27249

Vulnerability Analysis

This stored Cross-Site Scripting (XSS) vulnerability (CWE-79) in Adobe Experience Manager allows attackers with low-level privileges to inject malicious JavaScript code into form fields. The injected payload persists in the application's data store and executes whenever other users access the affected page, making it particularly dangerous as it requires no additional attacker interaction after the initial injection.

The vulnerability requires user interaction for successful exploitation—a victim must browse to a page containing the vulnerable field. However, the attack vector is network-accessible and the scope is changed, meaning the vulnerable component impacts resources beyond its security scope, potentially affecting other components or users within the same trust boundary.

Root Cause

The vulnerability stems from improper neutralization of input during web page generation (CWE-79). Adobe Experience Manager fails to properly sanitize user-supplied input in certain form fields before storing and rendering the content. This allows malicious script content to be persisted in the application and later rendered without proper encoding or escaping.

Attack Vector

The attack is conducted over the network and requires low privileges to execute. An attacker with basic access to the Adobe Experience Manager platform can identify vulnerable form fields and inject malicious JavaScript payloads. When other users—including administrators—navigate to pages containing these compromised fields, the malicious scripts execute within their browser context.

The stored nature of this XSS vulnerability means:

The payload persists across sessions and page loads
Multiple victims can be affected from a single injection
The attacker does not need to maintain an active session after injection
Scripts execute with the privileges of the viewing user

Detection Methods for CVE-2026-27249

Indicators of Compromise

Unusual JavaScript code or HTML tags stored in AEM form fields or content nodes
Unexpected script execution or browser behavior when accessing AEM-managed pages
User reports of suspicious pop-ups, redirects, or credential prompts on AEM content
Audit logs showing form submissions with encoded or obfuscated script content

Detection Strategies

Implement Content Security Policy (CSP) headers to detect and block inline script execution
Monitor AEM audit logs for suspicious content modifications by low-privileged users
Deploy web application firewalls (WAF) with XSS detection signatures
Conduct regular security scans of AEM content for stored malicious payloads

Monitoring Recommendations

Enable detailed logging for all form submissions and content modifications in AEM
Monitor for JavaScript execution patterns indicative of XSS exploitation
Alert on CSP violation reports that may indicate blocked XSS attempts
Track user session anomalies that could suggest session hijacking via XSS

How to Mitigate CVE-2026-27249

Immediate Actions Required

Apply the latest Adobe Experience Manager security update as referenced in APSB26-24
Review and audit existing AEM content for potentially injected malicious scripts
Implement or strengthen Content Security Policy (CSP) headers on AEM instances
Restrict content editing privileges to trusted users where possible

Patch Information

Adobe has released a security update addressing this vulnerability. Administrators should apply the patch referenced in the Adobe Experience Manager Security Advisory (APSB26-24). Organizations running Adobe Experience Manager versions 6.5.23 and earlier should update to the latest patched version immediately.

Workarounds

Implement strict Content Security Policy (CSP) headers to prevent inline script execution
Deploy input validation and output encoding at the application layer
Use web application firewalls (WAF) with XSS detection capabilities as an additional defense layer
Restrict access to form editing functionality to minimize the attack surface

bash

# Example CSP header configuration for Apache
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; frame-ancestors 'self';"