CVE-2025-62729: Soplanning Stored XSS Vulnerability

CVE-2025-62729 Overview

CVE-2025-62729 is a stored cross-site scripting (XSS) vulnerability in SOPlanning, an open-source online planning tool. The flaw exists in the /status endpoint, where an authenticated attacker can inject arbitrary HTML and JavaScript. The payload is persisted server-side and executed in the browsers of other users when they load pages that render status data. The vendor fixed the issue in SOPlanning version 1.55. The weakness is classified under CWE-79: Improper Neutralization of Input During Web Page Generation.

Critical Impact
An authenticated attacker can inject persistent JavaScript that executes in other users' browsers, enabling session theft, UI manipulation, or forced actions within the SOPlanning application.

Affected Products

SOPlanning versions prior to 1.55
SOPlanning /status endpoint (stored input handling)
Deployments accepting authenticated user submissions to status fields

Discovery Timeline

2025-11-20 - CVE-2025-62729 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-62729

Vulnerability Analysis

SOPlanning fails to sanitize or encode user-supplied input submitted to the /status endpoint. The application stores the input and later renders it as part of HTML output on multiple pages of the interface. Because the input is neither validated nor contextually escaped, an attacker can supply HTML tags and inline JavaScript that browsers interpret and execute. Exploitation requires an authenticated account, but any user with permission to create or modify status entries can plant the payload. Once stored, the payload triggers whenever another user loads a page that displays the affected status data.

Root Cause

The root cause is missing output encoding on data returned from the /status endpoint. Server-side code writes user-controlled values directly into HTML contexts without applying HTML entity encoding or a strict allow-list. This matches the classic pattern described in CWE-79, where injected script executes in the security context of the vulnerable origin.

Attack Vector

The attack is remote and requires low privileges plus a victim interaction, since a second user must load a page that renders the malicious status. A typical exploitation flow is:

The attacker authenticates to SOPlanning with a low-privilege account.
The attacker submits a crafted status value containing an HTML or JavaScript payload to the /status endpoint.
SOPlanning stores the payload without sanitization.
A second user, often with elevated privileges, opens a page that displays status information.
The victim's browser executes the injected script under the SOPlanning origin, enabling session cookie theft, forged requests, or UI redressing.

For additional context on the coordinated disclosure of SOPlanning issues, refer to the CERT Poland analysis of related SOPlanning vulnerabilities and the SO Planning project site.

Detection Methods for CVE-2025-62729

Indicators of Compromise

Status entries containing HTML tags such as <script>, <img onerror=...>, <svg onload=...>, or JavaScript URI schemes.
Unexpected outbound HTTP requests from user browsers to attacker-controlled domains shortly after loading SOPlanning pages.
Application log entries showing POST requests to /status with payloads containing angle brackets or event handler attributes.
New or modified status records created by low-privilege accounts and viewed by administrative users.

Detection Strategies

Inspect the SOPlanning database status table for stored values containing HTML markup or script constructs.
Enable web application firewall (WAF) rules that flag XSS signatures on requests to the /status endpoint.
Correlate status modifications with subsequent authenticated session anomalies, such as new sessions from unusual IPs.
Review browser Content Security Policy (CSP) violation reports for blocked inline script execution originating from SOPlanning pages.

Monitoring Recommendations

Log all writes to /status with the submitting user, timestamp, and full payload for forensic review.
Alert on any status entry whose rendered length exceeds baseline norms or contains characters like <, >, or " in unexpected positions.
Monitor for privilege escalation patterns following status views by administrators, including new admin accounts or permission changes.

How to Mitigate CVE-2025-62729

Immediate Actions Required

Upgrade SOPlanning to version 1.55 or later, which contains the vendor fix for CVE-2025-62729.
Audit existing status records and remove entries containing HTML or JavaScript payloads before administrators view affected pages.
Rotate session tokens and force reauthentication for all SOPlanning users after patching.
Review recent account creations and permission changes for signs of exploitation.

Patch Information

The vendor addressed the vulnerability in SOPlanning 1.55. Administrators should follow the upgrade instructions on the SO Planning project site and validate the deployed version after upgrade. No official vendor advisory URL is listed in the CVE record; confirm the fix by inspecting the release notes for version 1.55.

Workarounds

Restrict access to the /status endpoint using web server rules or reverse proxy filters until the upgrade is applied.
Deploy a Content Security Policy that forbids inline scripts and restricts script sources to trusted origins.
Limit account creation and the assignment of status-editing permissions to trusted users during the remediation window.
Place SOPlanning behind a WAF configured to block payloads matching XSS patterns on POST requests to /status.

bash

# Example nginx configuration adding a restrictive Content Security Policy
# and blocking obvious XSS payloads on the /status endpoint
server {
    listen 443 ssl;
    server_name soplanning.example.com;

    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'; base-uri 'self'" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "DENY" always;

    location /status {
        if ($request_method = POST) {
            if ($request_body ~* "(<script|onerror=|onload=|javascript:)") {
                return 403;
            }
        }
        proxy_pass http://127.0.0.1:8080;
    }
}