CVE-2026-75639: Adobe Experience Manager DOM XSS Vulnerability

CVE-2026-75639 Overview

CVE-2026-75639 is a DOM-based Cross-Site Scripting (XSS) vulnerability affecting Adobe Experience Manager (AEM). An attacker can manipulate the Document Object Model (DOM) environment to execute arbitrary JavaScript within the context of a victim's browser session. Exploitation requires user interaction, specifically that the victim visits a crafted webpage. The issue is classified under CWE-79 and results in a scope change, meaning the impact extends beyond the vulnerable component. The vulnerability is tracked in Adobe's security bulletin APSB26-98.

Critical Impact
Successful exploitation allows attackers to run malicious JavaScript in the victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the authenticated user.

Affected Products

Adobe Experience Manager (AEM)
Refer to Adobe Security Advisory APSB26-98 for specific affected versions
Deployments exposing authenticated user interfaces to end users

Discovery Timeline

2026-09-08 - CVE-2026-75639 published to the National Vulnerability Database (NVD)
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-75639

Vulnerability Analysis

CVE-2026-75639 is a DOM-based Cross-Site Scripting flaw in Adobe Experience Manager. Unlike reflected or stored XSS, DOM-based XSS occurs entirely on the client side. The vulnerable JavaScript reads attacker-controlled data from a DOM source and writes it to a sink that executes code, such as innerHTML, document.write, or eval. Because the payload never needs to reach the server in a form that triggers server-side filters, standard server-side sanitization is often bypassed.

Exploitation requires low-privilege authentication and user interaction, and it triggers a scope change. A scope change indicates the vulnerable component and the impacted component are different security authorities, so the injected script can affect resources outside the AEM component that processed the malicious input.

Root Cause

The root cause is improper neutralization of input during web page generation on the client side [CWE-79]. AEM client-side scripts consume data from an attacker-influenced DOM source without adequate encoding or validation before passing it to a JavaScript execution sink. This allows an attacker to break out of the intended data context and inject executable script.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker crafts a malicious URL or webpage embedding a payload that manipulates the DOM environment of an authenticated AEM user. When the victim visits the crafted page, the client-side script in AEM processes the payload and executes attacker-controlled JavaScript in the browser. The attacker can then read the authenticated session context, exfiltrate cookies or tokens, or perform actions the user is authorized to perform.

Specific proof-of-concept code has not been published, and no verified exploit is publicly available. See Adobe Security Advisory APSB26-98 for vendor technical details.

Detection Methods for CVE-2026-75639

Indicators of Compromise

Unusual outbound requests from user browsers to attacker-controlled domains after visiting AEM-related URLs
AEM access logs containing requests with encoded JavaScript payloads in URL fragments, query parameters, or referrer fields
Unexpected DOM modifications or script executions in AEM author or publish interfaces
Session tokens or authentication cookies observed being transmitted to unknown external hosts

Detection Strategies

Deploy Content Security Policy (CSP) reporting to capture script-src violations across AEM domains
Inspect web server and reverse proxy logs for suspicious URL fragments containing script keywords such as javascript:, onerror=, or <script
Monitor endpoint telemetry for browser processes spawning unexpected child processes after visiting AEM URLs
Correlate authentication events with anomalous administrative actions performed shortly after a user clicked an external link

Monitoring Recommendations

Enable centralized logging for AEM dispatcher and application-tier requests, and forward to a SIEM for correlation
Alert on CSP violation reports originating from AEM hostnames
Track referrer patterns for AEM sessions to identify users arriving from suspicious external URLs
Review browser extension and script telemetry on endpoints used by AEM authors and administrators

How to Mitigate CVE-2026-75639

Immediate Actions Required

Apply the patches described in Adobe Security Advisory APSB26-98 to all affected Adobe Experience Manager instances
Inventory AEM author, publish, and dispatcher nodes to confirm patch coverage across the environment
Restrict administrative and content-author access to trusted networks where feasible
Educate AEM users about the risk of clicking untrusted links while authenticated to AEM

Patch Information

Adobe has published fixes in security bulletin APSB26-98. Administrators should consult the bulletin for the list of fixed versions and apply the updated Adobe Experience Manager release or hotfix corresponding to their deployment. Verify successful patch application by checking the AEM version metadata after upgrade.

Workarounds

Enforce a strict Content Security Policy that blocks inline scripts and restricts script sources to trusted origins
Configure the AEM dispatcher to filter suspicious request parameters and fragments before they reach the application tier
Require re-authentication for sensitive administrative operations to reduce impact of a hijacked session
Where patching is delayed, limit exposure of AEM author instances to the public internet using VPN or IP allowlisting