CVE-2026-48299: Adobe Experience Manager XSS Vulnerability

CVE-2026-48299 Overview

CVE-2026-48299 is a stored Cross-Site Scripting (XSS) vulnerability affecting Adobe Experience Manager (AEM). The flaw allows a low-privileged authenticated attacker to inject malicious JavaScript into vulnerable form fields. When a victim browses to a page containing the affected field, the injected script executes in the victim's browser context. The vulnerability has a changed scope, meaning the impact extends beyond the vulnerable component. Adobe published guidance in security advisory APSB26-56.

Critical Impact
A low-privileged attacker can persist malicious scripts into AEM form fields, leading to session theft, credential harvesting, and unauthorized actions performed in the victim's browser.

Affected Products

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

Discovery Timeline

2026-06-09 - CVE-2026-48299 published to NVD
2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-48299

Vulnerability Analysis

The vulnerability is classified as [CWE-79] Improper Neutralization of Input During Web Page Generation. AEM fails to sanitize user-supplied content submitted through specific form fields before rendering it on subsequent page views. The unsanitized input is stored server-side and served to other users who access the affected page.

Because the scope is changed, the executed script can access resources beyond the vulnerable component's security authority. The attack requires user interaction, meaning the victim must browse to the page containing the malicious payload for the script to execute.

Root Cause

The root cause is missing or insufficient output encoding when rendering content stored from form field submissions. AEM accepts the attacker-controlled input, persists it, and later embeds it into HTML output without neutralizing characters such as <, >, and ". The browser parses the embedded payload as executable script rather than data.

Attack Vector

The attack is delivered over the network and requires the attacker to hold low-privileged credentials in AEM. The attacker submits a payload containing JavaScript through a vulnerable form field. The payload is stored and rendered to any user who visits the affected page. No verified public exploit code is available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

No verified proof-of-concept code is available. Refer to the Adobe Security Advisory APSB26-56 for vendor-supplied technical details.

Detection Methods for CVE-2026-48299

Indicators of Compromise

Form field submissions containing HTML tags such as <script>, <img onerror=>, or <svg onload=> stored in AEM content repositories.
Outbound browser requests from authenticated AEM sessions to unfamiliar domains, indicating credential or token exfiltration.
Unexpected modifications to AEM nodes by low-privileged author accounts.

Detection Strategies

Inspect AEM request logs for POST or PUT operations to form endpoints containing encoded script payloads or event handler attributes.
Enable Content Security Policy (CSP) reporting to surface inline script execution attempts on AEM-rendered pages.
Review the JCR (Java Content Repository) for stored properties containing HTML or JavaScript markup in fields expected to hold plain text.

Monitoring Recommendations

Audit AEM author and contributor account activity for anomalous form submissions and content edits.
Forward AEM dispatcher and application logs to a centralized analytics platform for correlation with browser telemetry.
Track DOM-based alerts from web application firewalls placed in front of AEM dispatcher instances.

How to Mitigate CVE-2026-48299

Immediate Actions Required

Apply the security updates referenced in Adobe Security Advisory APSB26-56 to all affected AEM instances.
Inventory AEM deployments to confirm versions 6.5.24, LTS SP1, and 2026.04 or earlier are identified and prioritized for patching.
Review and restrict the assignment of low-privileged author accounts to reduce the population of users who can submit form content.

Patch Information

Adobe released fixed builds for AEM 6.5, AEM LTS, and AEM Cloud Service. Customers running AEM as a Cloud Service receive the fix automatically through the managed service. On-premises and AMS customers must install the updated service pack or hotfix described in advisory APSB26-56.

Workarounds

Configure AEM dispatcher rules and a web application firewall to block requests containing script tags or event handler attributes in form field parameters.
Enforce a strict Content Security Policy that disallows inline scripts on AEM-rendered pages until the patch is applied.
Temporarily revoke form submission permissions from non-essential author groups while remediation is in progress.

bash

# Example dispatcher filter rule to block script payloads in form parameters
/0100 { /type "deny" /method "POST" /url '.*\.(html|json)$' /query '.*(<script|onerror=|onload=|javascript:).*' }