CVE-2026-75734 Overview
Adobe Experience Manager (AEM) contains a stored Cross-Site Scripting (XSS) vulnerability [CWE-79] that allows a low-privileged authenticated attacker to inject malicious JavaScript into vulnerable form fields. When a victim browses to the page rendering the injected content, the script executes in their browser under the AEM origin. The vulnerability has a changed scope, meaning the injected payload can affect resources beyond the vulnerable component.
Critical Impact
An authenticated attacker with low privileges can inject persistent JavaScript that executes in other users' browsers, enabling session theft, credential harvesting, and unauthorized actions on behalf of victims.
Affected Products
- Adobe Experience Manager (AEM Cloud Service)
- Adobe Experience Manager 6.5 LTS (base release)
- Adobe Experience Manager 6.5 LTS SP1 and SP2
Discovery Timeline
- 2026-09-08 - CVE CVE-2026-75734 published to the National Vulnerability Database
- 2026-09-10 - Last updated in NVD database
Technical Details for CVE-2026-75734
Vulnerability Analysis
The flaw is a stored XSS condition in Adobe Experience Manager form field handling. AEM fails to sufficiently sanitize or encode user-supplied input before persisting it and later rendering it in the response HTML. An authenticated user with content-authoring privileges can submit crafted input containing JavaScript payloads through affected form fields.
When another user, including higher-privileged administrators, visits the page containing the injected field, the browser parses and executes the payload. Because scope is changed, the impact extends beyond the vulnerable component to other security authorities within the same browser context. Attackers can leverage this to steal authentication cookies, perform actions in the AEM administrative interface, or pivot into internal systems.
Root Cause
The root cause is improper neutralization of input during web page generation [CWE-79]. AEM stores attacker-controlled content without applying context-appropriate output encoding when the data is rendered. The persistence of the payload amplifies the risk because the injected script fires for every user who loads the affected page.
Attack Vector
Exploitation requires network access to the AEM instance and a valid low-privileged account. The attacker submits a payload through a vulnerable form field and waits for a victim to visit the rendered page. User interaction is required on the victim side, but no additional privileges are needed to trigger execution. See the Adobe Security Advisory APSB26-98 for product-specific technical details.
Detection Methods for CVE-2026-75734
Indicators of Compromise
- Form field values in AEM content repositories containing <script>, javascript:, event handler attributes such as onerror= or onload=, or encoded variants of these strings.
- Unexpected outbound HTTP requests from authenticated AEM user sessions to attacker-controlled domains.
- Anomalous authoring activity from low-privileged accounts that modify shared form components or reusable content fragments.
Detection Strategies
- Review AEM audit logs for content modifications by non-administrative users touching form-related components or dialog fields.
- Inspect rendered pages and JCR nodes for stored HTML or script tags that should be plain text.
- Correlate web server access logs against Content Security Policy (CSP) violation reports to surface script executions from unexpected sources.
Monitoring Recommendations
- Enable CSP report-only mode across AEM publish and author instances and forward reports to a centralized SIEM for analysis.
- Monitor administrator sessions for unusual API calls or bulk exports initiated shortly after visiting author-editable pages.
- Alert on new or modified cq:Widget and form component nodes containing markup characters in expected text fields.
How to Mitigate CVE-2026-75734
Immediate Actions Required
- Apply the Adobe security update referenced in advisory APSB26-98 to all AEM Cloud Service and AEM 6.5 LTS deployments.
- Audit content authored since the exposure window for injected scripts and remove any malicious payloads found.
- Rotate session tokens and credentials for administrators who accessed potentially affected pages.
Patch Information
Adobe has published fixes in the Adobe Security Advisory APSB26-98. Customers running AEM Cloud Service receive updates through the managed release channel. Customers running AEM 6.5 LTS, including base, SP1, and SP2, must install the corresponding service pack or hotfix identified in the advisory.
Workarounds
- Restrict content authoring permissions to trusted users and remove authoring rights from accounts that do not require them.
- Deploy a strict Content Security Policy that disallows inline script execution on AEM publish endpoints.
- Place a web application firewall in front of AEM to filter form submissions containing suspicious HTML or script markup until patching is complete.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
