CVE-2026-48300: Adobe Experience Manager XSS Vulnerability

CVE-2026-48300 Overview

CVE-2026-48300 is a stored Cross-Site Scripting (XSS) vulnerability affecting Adobe Experience Manager (AEM) versions 6.5.24, LTS SP1, 2026.04, and earlier. A low-privileged attacker can inject malicious JavaScript into vulnerable form fields. When a victim browses to the affected page, the injected script executes in their browser. The vulnerability has a changed scope, meaning the attack can affect resources beyond the originally compromised component. Adobe published security advisory APSB26-56 to address the issue. The flaw maps to CWE-79: Improper Neutralization of Input During Web Page Generation.

Critical Impact
An authenticated low-privileged attacker can store malicious JavaScript that executes against any user who visits the affected AEM page, enabling session hijacking, credential theft, and unauthorized actions in the victim's authenticated context.

Affected Products

Adobe Experience Manager 6.5.24 and earlier
Adobe Experience Manager LTS SP1 and earlier
Adobe Experience Manager 2026.04 (AEM Cloud Service) and earlier

Discovery Timeline

2026-06-09 - CVE-2026-48300 published to NVD
2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-48300

Vulnerability Analysis

The vulnerability is a stored XSS issue in Adobe Experience Manager form fields. AEM is a content management platform used to author and deliver digital experiences across web and mobile channels. The affected form fields accept user input without sufficient output encoding or input sanitization. An attacker with authoring or contributor privileges can submit JavaScript payloads that AEM persists in the underlying content repository. When any subsequent user—including higher-privileged administrators—renders the page containing the stored payload, the browser executes the attacker-controlled script.

Because the CVSS scope is marked as changed (S:C), the script runs in a context that can affect resources outside the vulnerable component. In an AEM deployment, this typically means the payload can interact with the authoring console, Dispatcher-served pages, or federated identity sessions. The vulnerability requires user interaction (UI:R), meaning a victim must navigate to the affected page for exploitation to succeed.

Root Cause

The root cause is improper neutralization of user-controlled input rendered into HTML output [CWE-79]. AEM form components fail to apply context-aware encoding before persisting and serving field values, allowing HTML and script tokens to survive the rendering pipeline intact.

Attack Vector

The attack is network-reachable and requires low privileges plus user interaction. An attacker authenticates to AEM with a content-author or equivalent role, edits a vulnerable form component, and embeds a JavaScript payload in a field value. The payload is stored in the JCR (Java Content Repository) and served to any user who later accesses the page. No exploit code is currently public, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-48300

Indicators of Compromise

Unexpected <script>, onerror, onload, or javascript: tokens stored in AEM form field properties within the JCR
Outbound requests from authoring or publish nodes to attacker-controlled domains following page rendering
Anomalous content modifications by low-privileged author accounts targeting form components
Browser console errors or Content Security Policy (CSP) violations on AEM-rendered pages

Detection Strategies

Audit AEM audit logs (/var/audit) and replication logs for content modifications to form components by non-administrative users
Query the JCR for property values containing HTML or JavaScript syntax in form field nodes using AEM Query Builder or JCR-SQL2
Deploy CSP headers in report-only mode to surface inline script execution attempts originating from AEM pages

Monitoring Recommendations

Forward AEM access, audit, and Dispatcher logs to a centralized SIEM for correlation against author activity baselines
Monitor for spikes in POST requests to /content/forms/* or /libs/cq/* endpoints from authoring accounts
Alert on browser-side telemetry indicating script execution from unexpected origins on AEM-hosted pages

How to Mitigate CVE-2026-48300

Immediate Actions Required

Apply the Adobe security updates referenced in Adobe Security Advisory APSB26-56 for all affected AEM 6.5, LTS, and Cloud Service deployments
Review and restrict author and contributor role assignments to limit who can edit form components
Audit existing form content for stored payloads using JCR queries before patching to identify any pre-existing compromise

Patch Information

Adobe released fixed versions addressed in advisory APSB26-56. Customers running Adobe Experience Manager 6.5.24, LTS SP1, or 2026.04 and earlier should upgrade to the patched releases identified by Adobe. AEM as a Cloud Service customers receive the fix through the standard Adobe release channel. Refer to the Adobe Security Advisory APSB26-56 for exact target versions and download locations.

Workarounds

Configure AEM Dispatcher to filter or strip suspicious HTML and script tokens from cached page responses where feasible
Enforce a strict Content Security Policy that disallows inline script execution on AEM-served pages to reduce payload impact
Temporarily restrict edit permissions on affected form components to trusted administrative accounts until the patch is applied

bash

# Example Dispatcher filter snippet to deny suspicious request patterns
/0100 { /type "deny" /url '*<script*' }
/0101 { /type "deny" /url '*javascript:*' }
/0102 { /type "deny" /url '*onerror=*' }

# Example CSP header to mitigate inline script execution
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'"