CVE-2026-10731: Two-Factor Auth SQL Injection Vulnerability

CVE-2026-10731 Overview

CVE-2026-10731 is a SQL injection vulnerability affecting Nemon products. The flaw resides in the two_steps_auth_code parameter processed by the twoStepsAuthVerification function within the /user-login endpoint. The two-factor authentication (2FA) workflow is reachable without prior authentication, allowing unauthenticated remote attackers to inject arbitrary SQL statements into backend database queries. Successful exploitation enables database enumeration, creation of privileged user accounts, modification or deletion of stored records, and denial-of-service conditions. The vulnerability maps to CWE-89: Improper Neutralization of Special Elements used in an SQL Command.

Critical Impact
Unauthenticated attackers can execute arbitrary SQL queries on the backend database, leading to full data compromise and the unauthorized creation of privileged users.

Affected Products

Nemon products exposing the /user-login endpoint with the twoStepsAuthVerification function
Deployments where the two-factor authentication code parameter is reachable pre-authentication
Specific product versions are not enumerated in the published NVD record; refer to the INCIBE Security Notice on SQL Injection for vendor-confirmed scope

Discovery Timeline

2026-06-09 - CVE-2026-10731 published to NVD
2026-06-09 - Last updated in NVD database

Technical Details for CVE-2026-10731

Vulnerability Analysis

The vulnerability resides in the server-side handler twoStepsAuthVerification, which processes the two_steps_auth_code HTTP parameter submitted to the /user-login endpoint. User-supplied input is concatenated into a SQL statement without parameterization or sanitization, satisfying the conditions of [CWE-89]. Because the 2FA verification step is exposed before the primary authentication state is enforced, an attacker does not need valid credentials, a session, or a prior login challenge to reach the vulnerable code path. Any HTTP client capable of sending a request to /user-login can submit a crafted two_steps_auth_code value and influence query execution.

Root Cause

The root cause is the absence of parameterized queries or input validation in the twoStepsAuthVerification function. The 2FA code is treated as trusted SQL content rather than as a literal value bound through a prepared statement. Compounding the defect, the endpoint enforces no prior authentication state before invoking the database query, which removes a critical control that would otherwise limit reachability.

Attack Vector

Exploitation occurs over the network through a single unauthenticated HTTP request. An attacker submits a POST request to /user-login containing a malicious payload in the two_steps_auth_code field. The injected SQL can be used to enumerate schema and credential data via boolean or time-based techniques, insert new administrator accounts, alter stored authentication records, drop tables, or trigger expensive queries that exhaust database resources. No user interaction is required.

Verified exploitation code is not available at the time of writing. See the INCIBE Security Notice on SQL Injection for the coordinated disclosure details.

Detection Methods for CVE-2026-10731

Indicators of Compromise

HTTP POST requests to /user-login containing SQL metacharacters such as ', --, ;, UNION, SLEEP(, or BENCHMARK( within the two_steps_auth_code parameter
Unexpected administrative or privileged user accounts created in the application's user table without a corresponding provisioning workflow
Database error messages or anomalous query latency originating from the twoStepsAuthVerification code path

Detection Strategies

Inspect web server and application logs for requests to /user-login where the two_steps_auth_code value contains non-numeric characters or exceeds the expected code length
Enable database audit logging and alert on INSERT, UPDATE, or DELETE statements originating from the login service account outside normal authentication flows
Deploy WAF signatures targeting SQL injection payloads on the 2FA endpoint and review blocked events for repeated attempts from the same source

Monitoring Recommendations

Correlate failed login bursts with downstream database write activity to identify exploitation attempts that bypass front-end controls
Monitor for newly created accounts with elevated roles and validate against change management records
Baseline normal request rates and payload patterns for /user-login and alert on statistical deviations

How to Mitigate CVE-2026-10731

Immediate Actions Required

Apply the vendor-supplied patch referenced in the INCIBE Security Notice on SQL Injection as soon as it is available for the affected Nemon product
Restrict network access to the /user-login endpoint to trusted ranges where feasible until patching is complete
Audit the application's user and role tables for unauthorized privileged accounts and rotate credentials for accounts that show signs of tampering

Patch Information

Refer to the vendor advisory coordinated through INCIBE-CERT for patch availability and fixed version numbers. The published NVD entry for CVE-2026-10731 does not enumerate fixed builds; administrators should consult Nemon directly for the remediated release and confirm the patched build addresses the twoStepsAuthVerification input handling.

Workarounds

Deploy a Web Application Firewall rule that blocks SQL metacharacters in the two_steps_auth_code parameter of requests to /user-login
Enforce strict server-side validation that accepts only the expected numeric format and length for the 2FA code before it reaches the database layer
Require prior authentication state checks at the reverse proxy or application gateway so that the 2FA verification step cannot be invoked without an associated primary login attempt

bash

# Example WAF rule (ModSecurity) restricting the 2FA code parameter to digits
SecRule REQUEST_URI "@streq /user-login" \
    "id:1026731,phase:2,chain,deny,status:400,log,msg:'CVE-2026-10731 SQLi attempt on two_steps_auth_code'"
    SecRule ARGS:two_steps_auth_code "!@rx ^[0-9]{4,8}$" "t:none"