CVE-2026-30251: Interzen Zenshare Suite XSS Vulnerability

CVE-2026-30251 Overview

CVE-2026-30251 is a reflected cross-site scripting (XSS) vulnerability in Interzen Consulting S.r.l ZenShare Suite v17.0. The flaw resides in the login_newpwd.php endpoint, where the codice_azienda parameter is reflected into the response without proper sanitization. Attackers craft malicious URLs that execute arbitrary JavaScript in the victim's browser session when the link is opened. The issue is tracked under CWE-79 (Improper Neutralization of Input During Web Page Generation).

Critical Impact
Successful exploitation enables session hijacking, credential theft via injected login forms, and arbitrary actions performed in the authenticated user's context.

Affected Products

Interzen Consulting S.r.l ZenShare Suite v17.0
login_newpwd.php endpoint processing the codice_azienda parameter
Deployments exposing the password reset workflow to untrusted networks

Discovery Timeline

2026-04-02 - CVE-2026-30251 published to NVD
2026-04-09 - Last updated in NVD database

Technical Details for CVE-2026-30251

Vulnerability Analysis

The vulnerability exists in the password reset workflow of ZenShare Suite v17.0. The login_newpwd.php script accepts a codice_azienda (company code) parameter via the URL and embeds the value directly into the rendered HTML response. Because the application performs no output encoding or input validation, attacker-supplied JavaScript executes in the browser of any user who visits the crafted URL.

Reflected XSS requires user interaction, typically through a phishing link delivered by email or chat. Once the link is clicked, the injected payload runs under the origin of the ZenShare Suite application. Attackers can read DOM contents, exfiltrate session cookies that lack the HttpOnly flag, and replace the legitimate password reset form with an attacker-controlled version. The flaw is reachable without authentication, which expands the population of potential victims to any user who can be lured to the malicious URL.

Root Cause

The root cause is missing contextual output encoding when reflecting the codice_azienda GET parameter into HTML. The application trusts client-supplied input and does not apply HTML entity encoding, JavaScript escaping, or allowlist-based validation before rendering the value.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker delivers a crafted URL pointing to the ZenShare Suite login_newpwd.php endpoint with a malicious payload injected into the codice_azienda query parameter. The injected script executes in the victim's browser within the security context of the vulnerable application. See the GitHub PoC Repository for technical details on the parameter handling.

No verified proof-of-concept code is reproduced here. Refer to the published advisory for payload structure.

Detection Methods for CVE-2026-30251

Indicators of Compromise

HTTP GET requests to /login_newpwd.php containing script tags, event handlers (onerror=, onload=), or encoded JavaScript in the codice_azienda parameter
Referer headers pointing to external domains preceding requests to the password reset endpoint
Unexpected outbound requests from user browsers to attacker-controlled domains shortly after accessing ZenShare Suite URLs

Detection Strategies

Inspect web server access logs for codice_azienda values containing <, >, %3C, javascript:, or base64-encoded payloads
Deploy web application firewall (WAF) rules that flag XSS signatures targeting the ZenShare Suite password reset workflow
Correlate browser telemetry showing JavaScript execution originating from the ZenShare application with anomalous URL referrers

Monitoring Recommendations

Enable verbose HTTP logging on the ZenShare Suite web tier and forward logs to a centralized analytics platform
Alert on repeated requests to login_newpwd.php from a single source containing suspicious query string characters
Monitor email and messaging gateways for URLs targeting the vulnerable endpoint with abnormally long or encoded codice_azienda values

How to Mitigate CVE-2026-30251

Immediate Actions Required

Contact Interzen Consulting S.r.l for a fixed release or patched build of ZenShare Suite v17.0
Deploy WAF rules to block requests containing HTML or JavaScript metacharacters in the codice_azienda parameter
Educate users about phishing links that target the password reset workflow

Patch Information

No vendor patch is referenced in the NVD entry at the time of publication. Consult the vendor advisory and PoC repository for remediation status and monitor Interzen Consulting communications for fixed versions.

Workarounds

Apply server-side input validation to restrict codice_azienda to expected alphanumeric company code formats
Enforce contextual output encoding on all reflected parameters in login_newpwd.php
Set HttpOnly and Secure flags on session cookies to limit cookie theft via injected scripts
Implement a strict Content Security Policy (CSP) that disallows inline scripts and untrusted script sources

bash

# Example NGINX rule to block obvious XSS payloads on the affected endpoint
location /login_newpwd.php {
    if ($args ~* "(<|%3C|script|javascript:|onerror=|onload=)") {
        return 403;
    }
    # Add a baseline CSP header for defense in depth
    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'";
}