CVE-2026-75683: Adobe Experience Manager XSS Vulnerability

CVE-2026-75683 Overview

Adobe Experience Manager (AEM) contains a DOM-based Cross-Site Scripting (XSS) vulnerability tracked as CVE-2026-75683. An attacker can manipulate the Document Object Model (DOM) environment to execute malicious JavaScript in the victim's browser context. Successful exploitation requires user interaction, specifically that a target visits a crafted webpage. The vulnerability changes scope, meaning code executes across a security boundary distinct from the vulnerable component. Adobe published the fix in security bulletin APSB26-98. This weakness is classified under CWE-79: Improper Neutralization of Input During Web Page Generation.

Critical Impact
Attackers can execute arbitrary JavaScript in an authenticated user's browser session, enabling session theft, content manipulation, and unauthorized actions performed under the victim's identity.

Affected Products

Adobe Experience Manager AEM Cloud Service (all versions prior to the APSB26-98 fix)
Adobe Experience Manager 6.5 LTS (base release through Service Pack 2)
Adobe Experience Manager on-premise deployments matching the listed CPE ranges

Discovery Timeline

2026-09-08 - CVE-2026-75683 published to the National Vulnerability Database
2026-09-10 - Last updated in NVD database

Technical Details for CVE-2026-75683

Vulnerability Analysis

The vulnerability resides in client-side JavaScript that processes attacker-controlled input without proper sanitization. When AEM parses DOM sources such as location.hash, document.URL, or query parameters, unsanitized values reach a dangerous sink like innerHTML, document.write, or eval. The browser then executes the injected script under the origin of the AEM application.

Because the flaw operates entirely in the browser, the malicious payload never traverses the server, which limits server-side detection. The changed scope indicates that JavaScript executed in the AEM context can affect resources managed by a different security authority, such as an embedded editor iframe or an authoring console. Low-privileged authenticated users can trigger the flaw, and only limited user interaction is required.

Root Cause

The root cause is improper neutralization of input during web page generation on the client side [CWE-79]. AEM code reads data from a DOM source and passes it to a rendering sink without encoding or validation, allowing an attacker to break out of the intended data context and inject executable script.

Attack Vector

An attacker crafts a URL pointing to a vulnerable AEM page and embeds JavaScript in a fragment, query parameter, or referrer value. The attacker delivers this URL through phishing, malicious advertising, or a compromised third-party site. When an authenticated AEM user clicks the link, the vulnerable client script writes the payload into the DOM and executes it. The payload can then read session cookies not marked HttpOnly, exfiltrate authoring content, or issue authenticated requests to the AEM backend using the victim's session.

No verified public exploit code exists for this CVE. Refer to the Adobe Security Bulletin APSB26-98 for vendor-supplied technical details.

Detection Methods for CVE-2026-75683

Indicators of Compromise

Unusual outbound requests from AEM author or publish instances to attacker-controlled domains carrying base64 or URL-encoded data.
Web server access logs showing AEM URLs containing <script>, javascript:, onerror=, or encoded variants in query strings or fragments.
Unexpected content changes, new administrative users, or modified page templates in AEM created shortly after a user clicked an external link.

Detection Strategies

Deploy Content Security Policy (CSP) reporting to capture inline script violations and DOM manipulation attempts against AEM origins.
Inspect browser telemetry and endpoint logs for AEM sessions that spawn cross-origin fetches to unfamiliar hosts.
Correlate authoring activity with the referring URL to identify sessions where user actions followed a suspicious external navigation.

Monitoring Recommendations

Forward AEM Dispatcher and web server logs to a centralized platform for query and correlation. The Singularity Data Lake supports OCSF-normalized ingestion of web access logs to enable this analysis.
Alert on AEM user sessions producing anomalous API call volumes or content modifications outside baseline authoring patterns.
Monitor endpoint browser processes tied to AEM authors for script-based credential access and cookie theft using Singularity Endpoint behavioral AI.

How to Mitigate CVE-2026-75683

Immediate Actions Required

Apply the Adobe fixes referenced in bulletin APSB26-98 to AEM Cloud Service and AEM 6.5 LTS environments as the priority remediation step.
Restrict AEM authoring interfaces to trusted networks or a VPN to reduce exposure to attacker-supplied URLs.
Educate content authors and administrators to avoid clicking AEM links received from untrusted sources.

Patch Information

Adobe addressed CVE-2026-75683 in security bulletin APSB26-98. AEM Cloud Service customers receive the fix through the standard cloud release cadence. AEM 6.5 LTS customers must install the corresponding Service Pack or hotfix identified in the bulletin. Verify the deployed build version after patching to confirm the update took effect.

Workarounds

Enforce a strict Content Security Policy that blocks inline scripts and restricts script-src to known origins on AEM author and publish tiers.
Configure the AEM Dispatcher to reject requests containing script-like tokens in query parameters or fragments where feasible.
Set HttpOnly and Secure flags on all AEM session cookies to reduce the value of a successful XSS payload.

bash

# Example CSP header enforced at the AEM Dispatcher or reverse proxy
Header always set Content-Security-Policy "default-src 'self'; \
  script-src 'self' https://trusted-cdn.example.com; \
  object-src 'none'; \
  base-uri 'self'; \
  frame-ancestors 'self'; \
  report-uri /csp-report"

# Ensure session cookies are hardened
Header edit Set-Cookie ^(.*)$ $1;HttpOnly;Secure;SameSite=Strict