CVE-2025-43756: Liferay DXP Reflected XSS Vulnerability

CVE-2025-43756 Overview

CVE-2025-43756 is a reflected cross-site scripting (XSS) vulnerability affecting Liferay Portal and Liferay Digital Experience Platform (DXP). The flaw allows a remote authenticated user to inject arbitrary JavaScript code through the snippet parameter. When a victim loads a crafted URL, the injected script executes in the victim's browser under the Liferay origin. This enables session theft, unauthorized actions on behalf of the user, and content manipulation within the portal interface. The vulnerability is tracked under CWE-79: Improper Neutralization of Input During Web Page Generation.

Critical Impact
An authenticated attacker can execute arbitrary JavaScript in a targeted user's browser session, leading to session hijacking, credential theft, or unauthorized portal actions.

Affected Products

Liferay Portal 7.4.3.132
Liferay DXP 2025.Q1.0 through 2025.Q1.15 and 2025.Q2.0 through 2025.Q2.2
Liferay DXP 2024.Q1.13 through 2024.Q1.19

Discovery Timeline

2025-08-21 - CVE-2025-43756 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-43756

Vulnerability Analysis

The vulnerability is a reflected XSS flaw in the handling of the snippet request parameter within Liferay Portal and Liferay DXP. The affected endpoint reflects the parameter value into the rendered HTML response without proper output encoding or input sanitization. An authenticated attacker crafts a URL containing malicious JavaScript in the snippet parameter and delivers it to a signed-in user. When the target loads the URL, the payload executes in the browser under the Liferay application's origin.

Because the payload runs within an authenticated portal session, the attacker inherits the victim's privileges for the duration of script execution. This creates a pivot point for stealing session cookies, invoking authenticated APIs, or modifying portal content visible to the user.

Root Cause

The root cause is missing contextual output encoding when the snippet parameter is written back into the HTTP response body. The affected code paths trust user-controlled input and render it directly into HTML, allowing <script> tags and event handlers to be interpreted by the browser. See the Liferay Security Advisory CVE-2025-43756 for vendor-confirmed technical details.

Attack Vector

Exploitation requires an authenticated session on the vulnerable Liferay instance and a target user willing to click a crafted link. The attacker prepares a URL that includes a JavaScript payload in the snippet query parameter and delivers it through phishing, chat, or an embedded link inside the portal. On page load, the reflected payload executes in the victim's browser context, giving the attacker access to the victim's session state and any data reachable through the portal DOM.

No verified public proof-of-concept code is available for this issue. Refer to the vendor advisory for reproduction guidance.

Detection Methods for CVE-2025-43756

Indicators of Compromise

HTTP requests containing script tags, javascript: URIs, or HTML event handlers (for example onerror=, onload=) in the snippet query parameter.
Reflected response bodies where the snippet value appears unencoded inside HTML output.
Unusual outbound requests from authenticated user browsers to attacker-controlled domains shortly after loading a Liferay page with a snippet parameter.

Detection Strategies

Inspect web server and reverse proxy logs for requests to Liferay endpoints where the snippet parameter contains angle brackets, encoded script markers (%3Cscript), or common XSS payload patterns.
Deploy web application firewall (WAF) rules that flag reflected XSS signatures targeting Liferay URIs.
Correlate authenticated session activity with anomalous JavaScript-initiated requests originating from portal pages.

Monitoring Recommendations

Enable verbose HTTP request logging on Liferay front-end proxies and forward logs to a centralized analytics platform for pattern analysis.
Alert on repeated failed or unusual requests to Liferay pages that include the snippet parameter from a small set of source addresses.
Monitor Content Security Policy (CSP) violation reports to catch injected inline scripts blocked by browser policies.

How to Mitigate CVE-2025-43756

Immediate Actions Required

Upgrade Liferay Portal and Liferay DXP to a fixed release as listed in the Liferay Security Advisory CVE-2025-43756.
Review authenticated user accounts and revoke sessions for any users suspected of clicking crafted links.
Enforce a strict Content Security Policy to reduce the impact of any residual reflected XSS vectors.

Patch Information

Liferay has published fixed versions and remediation guidance in the vendor advisory. Administrators running Liferay Portal 7.4.3.132 or the listed DXP quarterly releases (2024.Q1.13–2024.Q1.19, 2025.Q1.0–2025.Q1.15, 2025.Q2.0–2025.Q2.2) should apply the corresponding update or hotfix documented by Liferay.

Workarounds

Deploy WAF rules that block or sanitize requests containing HTML or JavaScript payloads in the snippet parameter until patches are applied.
Restrict portal access to trusted networks or authenticated VPN users to reduce the exposure surface for delivery of malicious links.
Configure the Content-Security-Policy response header to disallow inline scripts and restrict script sources to trusted origins.

bash

# Example nginx Content-Security-Policy header for Liferay
add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'; frame-ancestors 'self';" always;