CVE-2026-4104: TeknoPass SQL Injection Vulnerability

CVE-2026-4104 Overview

CVE-2026-4104 is an authorization bypass vulnerability in Akmer Informatics Automation Industry and Trade Ltd. Co. TeknoPass. The flaw stems from a user-controlled SQL primary key that enables SQL Injection [CWE-89]. Attackers can manipulate primary key parameters to bypass authorization checks and execute arbitrary SQL statements against the backend database. The issue affects TeknoPass versions from 20210501 through 20260429. The vulnerability requires no authentication and no user interaction, and it is exploitable over the network.

Critical Impact

Unauthenticated attackers can bypass authorization controls and execute SQL injection against TeknoPass, leading to disclosure, modification, or destruction of database contents.

Affected Products

• Akmer Informatics TeknoPass version 20210501
• Akmer Informatics TeknoPass versions between 20210501 and 20260429
• Akmer Informatics TeknoPass version 20260429

Discovery Timeline

• 2026-06-04 - CVE-2026-4104 published to NVD
• 2026-06-04 - Last updated in NVD database

Technical Details for CVE-2026-4104

Vulnerability Analysis

The vulnerability resides in how TeknoPass handles primary key values supplied by clients. The application passes user-controlled primary key parameters directly into SQL queries without proper parameterization or authorization validation. This dual failure produces both an authorization bypass and a SQL injection condition. An attacker can substitute another user's primary key to access records they do not own, or inject SQL syntax to alter the query structure entirely.

Because the vulnerable path operates without authentication, any network-reachable attacker can interact with the affected endpoint. Successful exploitation can expose sensitive records, modify stored data, or impair database availability. The flaw is classified under [CWE-89] Improper Neutralization of Special Elements used in an SQL Command.

Root Cause

The root cause is the combination of two design defects. First, TeknoPass trusts client-supplied primary key values for authorization decisions, allowing horizontal privilege escalation. Second, the same values are concatenated into SQL statements rather than being bound as parameters, enabling SQL injection payloads to alter query semantics.

Attack Vector

An unauthenticated remote attacker sends crafted HTTP requests that modify the primary key parameter consumed by the vulnerable query. By substituting valid identifiers, the attacker retrieves data belonging to other users. By appending SQL syntax, the attacker can read, modify, or delete arbitrary database content. No user interaction is required.

No verified proof-of-concept code is publicly available. See the Turkey Cyber Security Advisory for vendor-coordinated technical details.

Detection Methods for CVE-2026-4104

Indicators of Compromise

• HTTP requests to TeknoPass endpoints containing SQL metacharacters such as ', ", --, ;, UNION, or OR 1=1 inside primary key parameters.
• Database error messages or unusually large response bodies returned from TeknoPass application logs.
• Access patterns where a single client iterates sequentially through primary key identifier values.

Detection Strategies

• Inspect web server and application logs for parameter tampering against TeknoPass URLs, focusing on numeric primary key fields receiving non-numeric input.
• Deploy web application firewall signatures for SQL injection patterns targeting the TeknoPass request paths.
• Correlate authentication logs with record access events to identify access to records outside the requesting account's scope.

Monitoring Recommendations

• Enable database query logging on the TeknoPass backend and alert on UNION SELECT, INFORMATION_SCHEMA, or stacked query constructs.
• Monitor for spikes in database errors, query duration anomalies, and unexpected data export volumes from TeknoPass service accounts.

How to Mitigate CVE-2026-4104

Immediate Actions Required

• Restrict network exposure of TeknoPass by placing it behind a VPN or IP allowlist until a patched build is deployed.
• Contact Akmer Informatics to obtain a fixed TeknoPass build later than version 20260429.
• Audit database logs and application logs for evidence of prior exploitation, focusing on anomalous primary key values and SQL error patterns.

Patch Information

Akmer Informatics is the responsible vendor. Refer to the Turkey Cyber Security Advisory for the authoritative remediation guidance and patched release information. Apply the vendor-supplied update to all TeknoPass instances running versions 20210501 through 20260429.

Workarounds

• Place a web application firewall in front of TeknoPass with rules that reject SQL metacharacters in primary key parameters.
• Enforce least-privilege database accounts for TeknoPass so that injection attempts cannot escalate beyond the application's data scope.
• Implement server-side authorization checks that validate record ownership independently of the supplied primary key before executing queries.

# Example WAF rule snippet (ModSecurity) to block SQL metacharacters
# in TeknoPass primary key parameters
SecRule ARGS:id "@rx [\'\";\-\-]|union|select|or\s+1=1" \
    "id:1026410401,phase:2,deny,status:403,\
     msg:'Possible SQLi targeting TeknoPass CVE-2026-4104'"