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Intro
CVE-2026-42097: Authentication Bypass via Flawed Model Parameter Validation
A critical authentication bypass vulnerability exists in Sparx Pro Cloud Server, tracked as CVE-2026-42097. This flaw, assigned a CVSS v4.0 base score of 9.3 (Critical), allows an unauthenticated, remote attacker to execute arbitrary SQL queries against the application’s backend database. The core issue lies in the server’s flawed authentication mechanism, which bases its access control decisions solely on the presence and value of the `model` query parameter in the requested URL.
Normally, when a legitimate client (like Sparx Enterprise Architect) makes a request, it includes the target model name in the `model` parameter of the query string. The server uses this parameter to enforce authentication. However, due to the vulnerability, an attacker can omit the `model` query parameter entirely. Instead, the attacker can place the model name within the binary blob of the POST request body.
The server fails to check that the model identifier is coming from the expected source (the URL). It will accept the model name from the POST body and process the request as if it came from an authenticated source. This effectively bypasses the authentication check. The vulnerable endpoint is SparxCloudLink.sseap, and the issue can be exploited via both TLS and non-TLS ports.
Once authentication is bypassed, the attacker can proceed to the next phase: SQL injection. Because the server does not properly sanitize the input from the binary blob, the attacker can inject arbitrary SQL commands. This is a classic case of improper input validation (CWE-89) combined with improper authentication (CWE-287). The attacker gains the ability to read, modify, or delete any data in the database, leading to a complete compromise of the system’s confidentiality, integrity, and availability. Only version 6.1 build 167 and below were confirmed vulnerable by researchers. The vendor has not responded, leaving the vulnerability status for newer versions unknown.
DailyCVE Form:
Platform: Sparx Pro Cloud
Version: ≤6.1 build 167
Vulnerability : Auth Bypass + SQLi
Severity: 9.3 Critical
date: 2026-05-19
Prediction: 2026-07-19
What Undercode Say
Undercode Analytics:
The exploitation log from affected Sparx PCS servers shows a distinct pattern. Legitimate traffic from EA (Enterprise Architect) clients includes the `model` query parameter. Malicious exploitation attempts have a consistent HTTP signature: the absence of `model` in the query string (making it ?) while the body length remains non-zero, indicating a model name or SQL payload is present. Monitoring for this specific anomaly is critical for early detection.
Detection Analytics (Bash):
Watch for suspicious requests to the vulnerable .sseap endpoint sudo tail -f /var/log/sparx/access.log | grep "POST /SparxCloudLink.sseap" | grep "\?\""
Payload Example (Python):
import requests target = "https://target-server.com/SparxCloudLink.sseap?" Crafted binary blob with model name and SQL injection payload = b"\x00\x00\x00\x01[bash]' OR '1'='1" response = requests.post(target, data=payload, verify=False) print(response.text)
Exploit
Prerequisites: Remote network access to the Pro Cloud Server’s web interface. No authentication or user interaction is required.
Attack Vector:
- Identify Target: Locate the Sparx Pro Cloud Server’s API endpoint, typically
/SparxCloudLink.sseap. - Craft Malicious Request: Construct a POST request to the endpoint, making sure the URL’s query string is empty (omit the `model` parameter).
- Inject Payload: In the POST body (binary blob), supply the model name followed by SQL injection commands (e.g.,
[bash]' OR '1'='1). - Bypass Auth: The server, expecting the model name in the URL, fails to authenticate the request because the URL lacks the required parameter. It incorrectly processes the model name and SQL commands from the POST body.
- Execute SQL: The injected SQL commands are executed by the database with the privileges of the server’s database connection, allowing for data exfiltration, modification, or deletion.
Protection
- Immediate Patching: Upgrade to a version newer than 6.1 build 167. Monitor the vendor’s official channels for a patch (none officially provided by vendor as of May 2026).
- Network Restrictions: Restrict access to the Pro Cloud Server’s web interface using a firewall to allow only connections from trusted IP addresses or VPN gateways.
- Web Application Firewall (WAF): Deploy a WAF rule to block any POST request to `/SparxCloudLink.sseap` that lacks the `model` parameter in the query string.
- Configuration Hardening: If possible, modify the server’s request handler to strictly require the `model` query parameter to be present and non-empty before processing any POST data. Reject any request that does not meet this criteria.
- Input Sanitization: As a temporary mitigation, ensure all user-supplied input, especially in binary POST bodies, is rigorously sanitized to prevent SQL injection if a bypass occurs. Apply parameterized queries to separate SQL logic from data.
Impact
- Complete Data Breach: An unauthenticated attacker can read all data stored in the Pro Cloud Server’s database, including sensitive model data, user credentials, and system configurations.
- Data Integrity Loss: The attacker can modify or delete arbitrary database content, leading to corruption of models and system malfunction.
- Lateral Movement: The compromised server can be used as a pivot point to gain further access into the internal network, compromising connected systems.
- Compliance Violation: A successful breach leads to severe violations of data protection regulations (e.g., GDPR, HIPAA) due to the exposure of potentially classified or proprietary information.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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