CVE-2024-6740: Openfind Mail2000 Stored XSS Vulnerability

CVE-2024-6740 Overview

CVE-2024-6740 is a stored cross-site scripting (XSS) vulnerability in Openfind's Mail2000 email platform. The product fails to properly validate email attachments, allowing unauthenticated remote attackers to inject JavaScript code inside attachment content. When a recipient opens the crafted attachment through the webmail interface, the injected script executes in the victim's browser session under the Mail2000 origin. The flaw is classified under [CWE-79] (Improper Neutralization of Input During Web Page Generation).

Critical Impact
Attackers can execute arbitrary JavaScript in the context of an authenticated webmail user, enabling session theft, credential harvesting, and unauthorized mailbox actions.

Affected Products

Openfind Mail2000 version 7.0
Openfind Mail2000 version 8.0

Discovery Timeline

2024-07-15 - CVE-2024-6740 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-6740

Vulnerability Analysis

Mail2000 renders email attachments without adequately sanitizing or encoding their contents before display. An attacker sends an email containing an attachment with embedded JavaScript payloads, for example an HTML or SVG file with <script> tags or event handlers. When the recipient previews or opens the attachment through the Mail2000 web interface, the browser interprets the payload as executable script rather than inert data.

Because the malicious content is stored on the mail server and delivered on every subsequent view, this is a persistent (stored) XSS rather than a reflected one. Exploitation requires no authentication for the sender and only requires the victim to open the attachment. The attack scope is changed, meaning script execution affects resources beyond the vulnerable component's original security context.

Root Cause

The root cause is missing output encoding and insufficient content-type enforcement on user-supplied attachment data. Mail2000 does not neutralize active content in attachments before rendering them through the web client, violating standard [CWE-79] guidance for handling untrusted input.

Attack Vector

The attack is network-based and requires user interaction. An unauthenticated remote attacker crafts an email with a weaponized attachment and sends it to any Mail2000 user. When the recipient opens the attachment in the browser, the embedded JavaScript executes with the privileges of the authenticated webmail session, potentially exfiltrating cookies, forwarding emails, or pivoting to internal resources.

No verified public proof-of-concept code is available. Refer to the Openfind ISAC Report and the TW-CERT Security Advisory for vendor-provided technical detail.

Detection Methods for CVE-2024-6740

Indicators of Compromise

Inbound emails carrying HTML, SVG, or XML attachments that contain <script> tags, onerror, onload, or javascript: URI schemes.
Unexpected outbound HTTP requests from webmail user sessions to attacker-controlled domains shortly after attachment access.
Anomalous mailbox rule creation, forwarding rules, or session cookie use from unfamiliar IP addresses following attachment interaction.

Detection Strategies

Inspect SMTP traffic and mail gateway logs for attachments whose MIME type is text/html, image/svg+xml, or application/xhtml+xml and that contain scripting constructs.
Correlate webmail access logs with browser-generated network calls to identify script execution originating from attachment previews.
Deploy content security policy violation reporting on the Mail2000 origin to surface unauthorized script execution attempts.

Monitoring Recommendations

Enable verbose logging on the Mail2000 web front end and forward logs to a centralized analytics platform for behavioral review.
Monitor for spikes in cross-origin requests, cookie access, or DOM manipulation events tied to attachment rendering paths.
Alert on authentication anomalies such as concurrent sessions from disparate geolocations following inbound email with attachments.

How to Mitigate CVE-2024-6740

Immediate Actions Required

Apply the vendor-supplied security update for Mail2000 as directed by the TW-CERT Security Update advisory.
Restrict in-browser rendering of HTML and SVG attachments; force download-only handling until the patch is verified in place.
Notify Mail2000 users to avoid opening unexpected attachments, particularly HTML, SVG, or script-bearing file types.

Patch Information

Openfind has released a security update addressing CVE-2024-6740. Administrators should consult the Openfind ISAC Report for fixed build numbers and installation procedures applicable to Mail2000 7.0 and 8.0 deployments.

Workarounds

Configure the mail gateway to strip or quarantine attachments with active content types before delivery to Mail2000 mailboxes.
Enforce a strict Content-Security-Policy header on the webmail application to block inline script execution.
Serve attachments with Content-Disposition: attachment and a neutral MIME type such as application/octet-stream to prevent inline browser rendering.

bash

# Example nginx snippet to harden attachment delivery
location /mail2000/attachments/ {
    add_header Content-Security-Policy "default-src 'none'; sandbox;" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header Content-Disposition "attachment" always;
}