CVE-2026-31070: Pharmacy Management Privilege Escalation

CVE-2026-31070 Overview

CVE-2026-31070 is a privilege escalation vulnerability in the LalanaChami Pharmacy Management System at commit 5c3d028. The /api/user/signup endpoint fails to validate the role parameter submitted in the request body. Unauthenticated remote attackers can self-assign an administrative role during account registration. The flaw maps to CWE-269: Improper Privilege Management and stems from trusting client-supplied input for authorization decisions.

Critical Impact

Any remote user can register an account with administrator privileges, gaining full control over the pharmacy management application and its data.

Affected Products

• LalanaChami Pharmacy Management System at commit 5c3d02888631166649856f71d542387114b3010b
• Backend route handler backend/routes/user.js
• The /api/user/signup registration endpoint

Discovery Timeline

• 2026-05-19 - CVE-2026-31070 published to NVD
• 2026-05-20 - Last updated in NVD database

Technical Details for CVE-2026-31070

Vulnerability Analysis

The Pharmacy Management System exposes a public signup endpoint that accepts a JSON body containing standard registration fields. The handler in backend/routes/user.js persists the user record using values copied directly from the request body, including a role attribute that governs access control. Because the server performs no allowlist check on the role field, a caller can supply admin (or any other elevated role recognized by the application) and receive an account with those privileges on creation.

This is a textbook mass-assignment and broken access control issue. The endpoint does not require prior authentication, does not enforce role assignment server-side, and does not separate self-service registration from administrative provisioning. Attackers reach the highest privilege tier without any vulnerability chaining.

Root Cause

The root cause is improper privilege management [CWE-269]. The signup handler trusts client-supplied role data instead of defaulting new accounts to a non-privileged role on the server. No middleware enforces that only authenticated administrators may set the role field.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker sends a single HTTP POST request to /api/user/signup with a JSON payload that includes a role field set to an administrative value. The server stores the record and returns valid credentials, after which the attacker logs in with administrator access. Refer to the GitHub repository source code and the GitHub Gist code snippet for the vulnerable handler.

Detection Methods for CVE-2026-31070

Indicators of Compromise

• POST requests to /api/user/signup whose JSON body contains a role field, particularly values such as admin or administrator.
• New user records in the application database with elevated roles but no corresponding administrative provisioning event.
• Successful logins from newly created accounts followed immediately by privileged actions such as user management or data export.

Detection Strategies

• Inspect web server and application logs for signup payloads that include a role parameter and alert on any non-default value.
• Correlate account creation events with subsequent role changes or sensitive API calls within short time windows.
• Run static analysis on backend/routes/user.js to flag direct assignment from req.body to persisted role attributes.

Monitoring Recommendations

• Enable verbose request body logging on authentication and registration endpoints, with redaction for passwords.
• Forward application and reverse proxy logs to a centralized analytics platform for anomaly detection on privilege assignment.
• Periodically audit the users collection for accounts with administrative roles created outside an approved workflow.

How to Mitigate CVE-2026-31070

Immediate Actions Required

• Patch backend/routes/user.js so the signup handler ignores any role field in the request body and forces new accounts to a non-privileged default.
• Audit the user store and remove or downgrade any unauthorized administrator accounts created since deployment.
• Restrict network exposure of the application until a fix is deployed, for example by placing it behind authenticated access controls.

Patch Information

No official upstream patch is referenced in the CVE data. Operators must apply a source-level fix that removes client control over the role field and adds an explicit administrative provisioning path requiring an existing admin session. Review the vulnerable line in user.js when implementing the change.

Workarounds

• Deploy a reverse proxy or web application firewall rule that strips or rejects requests to /api/user/signup containing a role field.
• Configure the database to enforce a default non-privileged role at the schema layer so application bugs cannot override it.
• Disable public registration entirely and provision accounts manually until the code fix is in place.

# Example WAF/proxy rule: reject signup requests that include a role parameter
# NGINX with njs or equivalent middleware
location = /api/user/signup {
    if ($request_body ~* "\"role\"\s*:") {
        return 400 "role field not permitted in signup";
    }
    proxy_pass http://backend;
}