CVE-2026-4104: Critical SQL Injection Vulnerability in TeknoPass
TL;DR - CVE-2026-4104 is a critical SQL injection issue in TeknoPass, rated CVSS 9.8. - Affected versions are
20210501through20260429; fixed version is not confirmed publicly. - No confirmed in-the-wild exploitation or public PoC is available, but defenders should treat internet-exposed instances as high risk.
| Field | Value |
|---|---|
| CVE ID | CVE-2026-4104 |
| CVSS score | 9.8 (Critical) |
| Attack vector | Not explicitly published in the available source data; defenders should assume remote exposure risk given the score and vulnerability class |
| Auth required | Not explicitly published in the available source data; defenders should assume low or no attacker prerequisites until vendor guidance says otherwise |
| Patch status | Vendor/government advisory exists, but fixed version is not confirmed from accessible source material |
Vulnerability at a glance
CVE-2026-4104 is described by NVD as an authorization bypass through a user-controlled SQL primary key in Akmer Informatics Automation Industry and Trade Ltd. Co. TeknoPass, allowing SQL injection. That wording matters because it suggests this is not just a generic input-validation bug. It likely involves attacker control over an identifier used to select or update records, combined with missing authorization checks and unsafe SQL query construction.
The affected range published in the NVD description is explicit: TeknoPass versions 20210501 through 20260429. At the time of writing, a fixed version number is not confirmed from the available advisory content retrievable in this session. That means defenders cannot safely assume that an upgrade is available unless they validate directly with the vendor or an authoritative bulletin. In the absence of a confirmed fix, organizations should prioritize exposure reduction and application-layer monitoring.
What this vulnerability means in practice
A user-controlled primary key in a SQL-backed application is often used in requests such as viewing a user record, loading a credential entry, retrieving access rights, or modifying a workflow object. If that key is passed into backend SQL without proper parameterization, an attacker may be able to alter the query logic. If authorization checks are also weak, the attacker may not need legitimate access to the target record or function.
In practical terms, a successful exploit could let an attacker read unauthorized data, modify stored records, create or elevate accounts, or disrupt service depending on the database permissions granted to the application. Because the vulnerability description combines authorization bypass and SQL injection, defenders should consider both direct data theft and privilege abuse. Even if no public exploit exists yet, this bug class is commonly weaponized quickly once researchers or attackers understand the request path.
Technical Notes
A representative unsafe pattern for this type of flaw looks like this:
SELECT * FROM users WHERE id = '$REQUESTED_ID';
If REQUESTED_ID is attacker-controlled and not parameterized, malicious input can alter the query:
GET /api/user?id=1' OR '1'='1
A safer implementation uses parameterized queries and explicit authorization checks before database access:
cursor.execute("SELECT * FROM users WHERE id = %s AND owner_id = %s", (user_id, session_user))
Affected versions and exposure assumptions
The published vulnerable range is 20210501 through 20260429. That is the only versioning detail confirmed in the source material provided. The fixed version number is unknown. If you run TeknoPass and your deployed build falls anywhere in that range, you should currently treat it as potentially vulnerable until proven otherwise by the vendor.
Because the available data does not include a reliable deployment model, defenders should inventory both internet-exposed and internally reachable TeknoPass systems. SQL injection vulnerabilities are often discussed as external web app issues, but internal exposure still matters. A malicious insider, compromised VPN session, or attacker who already has a foothold inside the network could still target the application if access controls are weak.
| Version status | Detail |
|---|---|
| Affected versions | 20210501 through 20260429 |
| Fixed version | Not confirmed from available public source material |
| Advisory availability | Government bulletin/reference exists |
| Defender assumption | If running a version in the published range, assume vulnerable until vendor confirmation says otherwise |
Exploitation status and risk context
At this time, in-the-wild exploitation is not confirmed from the available sources. The issue is not listed in CISA’s Known Exploited Vulnerabilities catalog based on the research note, which means there is no CISA-backed evidence at present that active exploitation has been formally established. That said, absence from KEV does not mean low risk. Many vulnerabilities are exploited before they appear in broad public reporting, and some never make it into KEV despite real-world abuse.
Likewise, a public proof of concept is not confirmed from the accessible references used here. That is an important distinction: defenders should not say “there is no PoC” as a fact, only that no public PoC was confirmed from available sources. In the absence of exploitation telemetry or exploit code, security teams should fall back to first principles: a critical SQL injection in an access-control path is inherently high risk, especially if the application is reachable over HTTP or HTTPS.
Prioritization for defenders
This vulnerability should be treated as high-priority because of three factors: the critical 9.8 score, the SQL injection class, and the authorization bypass wording. Even without confirmed exploitation, the combination suggests a path to serious confidentiality and integrity impact. If TeknoPass stores identity, access, workflow, or credential-related information, the blast radius could be significant.
For triage, prioritize systems that are externally reachable, handle sensitive data, or are shared across departments or tenants. Then assess whether the application database account has broad privileges such as write access across multiple tables. The less constrained the DB account, the more damaging a successful injection may be. If you cannot patch immediately because the fixed version is unknown, strong compensating controls and monitoring become the difference between a theoretical risk and an incident you can detect early.
Detection and hunting guidance
Without vendor-provided IOCs or a confirmed exploit chain, detection has to focus on common SQL injection indicators and suspicious access to TeknoPass endpoints that use record identifiers, object IDs, or primary-key-like parameters. Start by identifying URLs, API paths, form fields, and POST bodies that reference id, userId, recordId, pk, or similarly named parameters. Then review reverse proxy, WAF, application, and database logs for payloads containing quote characters, comment markers, boolean conditions, union operators, or time-delay functions.
You should also look for mismatches between authenticated user context and accessed object identifiers. The authorization bypass angle means exploitation may not always look like classic noisy SQLi. An attacker may simply iterate through IDs or pass crafted values to retrieve data they should not be able to access. Correlate requests by session, source IP, and object identifier to spot enumeration, cross-tenant access, or access to non-owned records.
Technical Notes
Example suspicious HTTP log patterns to hunt for:
'id=' OR '1'='1
id=1--
id=1%27%20OR%20%271%27=%271
UNION SELECT
SLEEP(
WAITFOR DELAY
Example Sigma-like logic for web logs:
title: Potential TeknoPass SQLi Attempt
logsource:
category: webserver
detection:
selection:
cs-uri-query|contains:
- "id="
- "userId="
- "recordId="
- "pk="
keywords:
cs-uri-query|contains:
- "' OR '1'='1"
- "UNION SELECT"
- "--"
- "/*"
- "SLEEP("
- "WAITFOR DELAY"
condition: selection and keywords
level: high
Example Splunk search against HTTP logs:
index=web sourcetype IN (nginx,apache,iis)
("id=" OR "userId=" OR "recordId=" OR "pk=")
("' OR '1'='1" OR "UNION SELECT" OR "--" OR "/*" OR "SLEEP(" OR "WAITFOR DELAY")
| stats count min(_time) as firstSeen max(_time) as lastSeen by src_ip, uri, user_agent, http_method
If you have database logging enabled, watch for syntax errors or anomalous query patterns generated by the application account:
-- Examples to investigate in DB audit/error logs
syntax error near "'"
unterminated quoted string
SELECT ... WHERE id = '1' OR '1'='1'
Mitigation and patching
The most important limitation in current public data is that the fixed version number is not confirmed. The affected range is known, but the exact release containing a fix is not. That means your first action should be to obtain authoritative remediation guidance from the vendor or the referenced bulletin source. Until that happens, defenders should not claim that a specific upgrade target is safe.
If TeknoPass is internet-facing, reduce exposure immediately. Place the application behind a VPN or restricted reverse proxy where possible, limit source IP ranges, and enforce MFA for any administrative path around it. If segmentation is available, restrict the application so only required users and systems can reach it. On the application security side, use WAF rules to block common SQLi metacharacters and signatures against identifier parameters. WAFs are not a substitute for a code fix, but they can reduce opportunistic exploitation while you verify patch status.
Technical Notes
If TeknoPass is deployed behind NGINX, an example temporary block rule for suspicious query strings might look like:
map $query_string $block_sqli {
default 0;
~*(\bUNION\b|\bSELECT\b|%27|'|--|/\*|\bSLEEP\s*\() 1;
}
server {
if ($block_sqli) {
return 403;
}
}
Example ModSecurity rule for a compensating control:
SecRule ARGS_NAMES "@rx ^(id|userId|recordId|pk)$" \
"id:4104001,phase:2,deny,status:403,msg:'Possible TeknoPass SQLi attempt',chain"
SecRule ARGS "@rx (?i:(\bunion\b|\bselect\b|--|/\*|%27|'|\bsleep\s*\(|\bwaitfor\b))"
If a package-based upgrade path exists in your environment, use your normal package manager only after confirming the fixed version from the vendor. Generic examples:
# Debian/Ubuntu example - verify vendor-provided fixed version before running
sudo apt update
apt-cache policy teknopass
sudo apt install teknopass=<confirmed-fixed-version>
# RHEL-family example - verify vendor-provided fixed version before running
sudo dnf check-update teknopass
sudo dnf upgrade teknopass-<confirmed-fixed-version>
If no fixed version is yet available, implement a temporary workaround plan: 1. restrict network exposure, 2. enable detailed web and DB logging, 3. deploy WAF filtering on key parameters, 4. review application DB account permissions, and 5. monitor for unauthorized record access by ID.
References
The following sources were available and verifiable from the research note used for this article:
- NVD CVE record: https://nvd.nist.gov/vuln/detail/CVE-2026-4104
- Referenced advisory/bulletin: https://siberguvenlik.gov.tr/guvenlik-bildirimleri/detay/tr-26-0309
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
For further reading, check our article on how to collect volatile evidence during incident response and our glossary entry on what is Evil Twin.
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