CVE-2026-48304: Adobe Experience Manager XSS Vulnerability

CVE-2026-48304 Overview

CVE-2026-48304 is a stored Cross-Site Scripting (XSS) vulnerability affecting Adobe Experience Manager (AEM). The flaw resides in form field handling and allows a low-privileged authenticated attacker to inject malicious JavaScript. The injected payload executes in a victim's browser when the victim views the page containing the affected form field. The vulnerability has a changed scope, meaning exploitation can impact resources beyond the vulnerable component. Adobe published advisory APSB26-56 to address the issue.

Critical Impact
An authenticated attacker with low privileges can persist arbitrary JavaScript in AEM-rendered pages, enabling session theft, credential harvesting, and actions performed 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 and earlier (including AEM Cloud Service)

Discovery Timeline

2026-06-09 - CVE-2026-48304 published to NVD
2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-48304

Vulnerability Analysis

The vulnerability is classified as stored Cross-Site Scripting [CWE-79]. Adobe Experience Manager fails to properly sanitize user-supplied input submitted through specific form fields. The application persists the unsanitized input and later renders it as HTML when other users view the affected page. Browsers interpret the embedded JavaScript and execute it under the origin of the AEM application.

The attack requires the attacker to hold low-privileged credentials within AEM. User interaction is also required, since the victim must navigate to the page containing the malicious field. Because the scope is changed, the executed script can affect resources outside the vulnerable form component, including authenticated sessions for AEM administrators and content authors. Successful exploitation compromises the confidentiality and integrity of data accessible through the victim's browser session.

Root Cause

The root cause is insufficient output encoding and input validation within AEM form field processing. The application stores attacker-controlled markup and emits it into HTML responses without contextual escaping. Adobe has not published low-level details of the affected component beyond the security bulletin.

Attack Vector

An authenticated attacker injects a JavaScript payload into a vulnerable form field through the AEM authoring interface or an exposed form submission endpoint. The payload is stored server-side. When a victim with an active session loads the page rendering the field, the browser executes the script. The attacker can then exfiltrate cookies, abuse CSRF tokens, or pivot to authenticated AEM actions.

No public proof-of-concept exploit is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog. Refer to the Adobe Experience Manager Security Advisory APSB26-56 for vendor-confirmed technical details.

Detection Methods for CVE-2026-48304

Indicators of Compromise

Form field values in the AEM JCR repository containing <script>, javascript:, onerror=, onload=, or encoded variants such as <script>.
Outbound browser requests from authenticated AEM sessions to unexpected external domains, indicative of cookie or token exfiltration.
Unexpected modifications to AEM content or user accounts performed by authenticated sessions shortly after viewing pages with user-submitted form data.

Detection Strategies

Review AEM access logs for POST requests to form submission endpoints containing HTML or JavaScript syntax in field parameters.
Run repository queries against cq:Page and nt:unstructured nodes to identify stored values containing script tags or event handler attributes.
Correlate authoring activity from low-privileged accounts with subsequent administrator page views to identify potential targeting patterns.

Monitoring Recommendations

Enable verbose request logging on the AEM dispatcher and forward to a centralized SIEM or data lake for retrospective hunting against XSS signatures.
Monitor browser security telemetry such as Content Security Policy violation reports submitted by AEM-rendered pages.
Alert on creation or modification of AEM components by accounts with content-authors or equivalent low-privileged roles outside of normal change windows.

How to Mitigate CVE-2026-48304

Immediate Actions Required

Apply the security updates referenced in Adobe security bulletin APSB26-56 to all AEM on-premises, LTS, and Cloud Service instances.
Audit AEM user accounts and remove unnecessary authoring privileges to reduce the population of accounts that meet the low-privilege prerequisite.
Inspect existing form field content for stored payloads and sanitize or purge entries containing executable markup.

Patch Information

Adobe released fixed versions addressing CVE-2026-48304 for AEM 6.5.24, AEM LTS SP1, and AEM 2026.04, including AEM as a Cloud Service. Update guidance and download links are published in the Adobe Experience Manager Security Advisory. AEM Cloud Service customers receive the fix through the standard Adobe-managed update channel.

Workarounds

Deploy a strict Content Security Policy on AEM-published sites to block inline script execution and restrict script sources.
Configure the AEM dispatcher and any upstream web application firewall to filter form submissions containing script tags, event handlers, and javascript: URIs.
Restrict access to authoring environments to trusted networks and enforce multi-factor authentication for all AEM accounts.

bash

# Example AEM dispatcher filter rule to block script-like payloads in POST bodies
/0100 { /type "deny" /method "POST" /url "*" /body '(?i)(<script|onerror=|onload=|javascript:)' }