CVE-2025-62320: HCLTech Unica XSS Vulnerability

CVE-2025-62320 Overview

CVE-2025-62320 is an HTML Injection vulnerability affecting multiple products in the HCL Unica marketing platform suite. The flaw exists because the web application does not properly validate or sanitize user-supplied input before rendering it on a webpage. An attacker can inject arbitrary HTML markup into application responses. When the victim's browser loads the affected page, embedded HTML elements can trigger automatic requests to attacker-controlled external resources. The issue is tracked as CWE-79 and requires user interaction to exploit successfully.

Critical Impact

Successful exploitation allows attackers to inject malicious HTML content, manipulate page rendering, and trigger unauthorized outbound requests from victim browsers, potentially enabling phishing, credential theft, or data exfiltration.

Affected Products

• HCL Unica, Unica Audience Central, Unica Campaign
• HCL Unica Centralised Offer Management, Unica Contact Central, Unica Interact
• HCL Unica Journey, Unica Plan, Unica Segment Central

Discovery Timeline

• 2026-03-17 - CVE-2025-62320 published to NVD
• 2026-05-11 - Last updated in NVD database

Technical Details for CVE-2025-62320

Vulnerability Analysis

The vulnerability is classified as Improper Neutralization of Input During Web Page Generation, commonly known as HTML Injection and a subclass of Cross-Site Scripting (XSS). The affected HCL Unica components accept user-controlled input through web request parameters and reflect that input into HTML responses without applying output encoding or input sanitization. Because the injected content is parsed as markup by the browser, an attacker can introduce tags such as <img>, <iframe>, or <link> referencing remote endpoints. The browser then issues automatic requests to those endpoints when the page loads. Exploitation requires the victim to interact with a crafted link or page, and the scope is changed because the impact affects components beyond the vulnerable application.

Root Cause

The root cause is missing or insufficient output encoding when rendering user-controlled data into HTML contexts. The application trusts input from request parameters or stored fields and writes that data directly into the response body. Without HTML entity encoding of characters such as <, >, ", and ', browsers interpret the input as markup rather than text.

Attack Vector

An attacker crafts a URL or form submission containing HTML payload tags targeting a vulnerable Unica endpoint. The attacker delivers the link to an authenticated or unauthenticated user via email, chat, or another web page. When the victim opens the link, the injected HTML executes within the trusted application origin, triggering outbound requests, rendering attacker-controlled UI elements, or facilitating phishing overlays.

No verified proof-of-concept code is publicly available for CVE-2025-62320.
Refer to the HCL Software Knowledge Base advisory for technical specifics.

Detection Methods for CVE-2025-62320

Indicators of Compromise

• Web server access logs containing request parameters with HTML tag fragments such as <img, <iframe, <svg, or <link targeting Unica endpoints.
• Unexpected outbound HTTP/HTTPS requests originating from user browsers to unfamiliar domains immediately after loading Unica pages.
• Application response bodies containing reflected user input rendered as live HTML elements rather than encoded text.

Detection Strategies

• Deploy web application firewall (WAF) rules to flag requests containing HTML tag patterns directed at Unica application paths.
• Review application logs for parameter values containing angle brackets, event handler attributes, or URL-encoded equivalents (%3C, %3E).
• Perform dynamic application security testing (DAST) against Unica input fields to identify reflected and stored injection points.

Monitoring Recommendations

• Monitor outbound DNS and HTTP traffic from user workstations for connections to newly registered or low-reputation domains following Unica session activity.
• Enable Content Security Policy (CSP) violation reporting to surface unexpected resource loads originating from Unica pages.
• Correlate browser referrer headers with Unica URLs to identify users who visited crafted injection links.

How to Mitigate CVE-2025-62320

Immediate Actions Required

• Apply the security update referenced in the HCL Software Knowledge Base Article KB0129460 for all deployed Unica components.
• Inventory all instances of HCL Unica, Unica Campaign, Unica Interact, Unica Journey, Unica Plan, and related modules across the environment.
• Restrict external access to Unica administrative interfaces until patching is complete.

Patch Information

HCL Software has published remediation guidance in the vendor advisory. Administrators should consult the HCL Software Knowledge Base Article for fixed version details and upgrade instructions specific to each Unica module.

Workarounds

• Deploy a WAF policy that blocks or strips HTML tag characters from query string and form parameters submitted to Unica endpoints.
• Enforce a strict Content Security Policy that restricts image, frame, and script sources to trusted origins, reducing the impact of injected markup.
• Train users to avoid clicking unsolicited links referencing internal Unica URLs and report suspicious messages to the security team.

# Example nginx CSP header to limit external resource loads from Unica responses
add_header Content-Security-Policy "default-src 'self'; img-src 'self' data:; frame-src 'self'; connect-src 'self'; report-uri /csp-report" always;