CVE-2026-51152 in QD
Summary
by MITRE • 08/31/2026
Server-side request forgery (SSRF) in the /har/test endpoint in QD 20220208 through 20250803. Fetcher.build_request() in libs/fetcher.py constructs an httpclient.HTTPRequest from user-supplied JSON without validating URL scheme, host, or IP range. The /har/test handler does not require authentication, enabling unauthenticated remote attackers to force the QD server to send arbitrary HTTP requests to internal network resources and cloud metadata endpoints. validate_cert is set to False, disabling TLS verification.
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Analysis
by VulDB Data Team • 08/31/2026
The vulnerability identified in this analysis represents a critical Server-Side Request Forgery (SSRF) flaw located within the /har/test endpoint of QD software versions spanning from 20220208 through 20250803. This specific implementation defect stems directly from improper input validation and sanitization mechanisms in the Fetcher.build_request function found in libs/fetcher.py. The core technical failure occurs when this function constructs an httpclient.HTTPRequest object using user-supplied JSON data without performing any rigorous checks on the URL scheme, host address, or IP range. By failing to restrict the destination of outgoing requests, the application allows attackers to dictate where the server directs its network traffic, effectively turning the vulnerable service into a proxy for arbitrary HTTP requests.
The operational impact of this vulnerability is significantly amplified by two critical configuration factors: the lack of authentication requirements and the disabling of TLS certificate verification. The /har/test handler does not require any form of user authentication, which means that unauthenticated remote attackers can exploit this flaw from anywhere on the network or over the internet if the service is exposed. Furthermore, because validate_cert is explicitly set to False, the application will accept self-signed certificates and invalid SSL/TLS configurations without raising errors. This combination allows an attacker not only to access internal resources but also to interact with services that use non-standard or expired security credentials, broadening the scope of potential attacks beyond standard HTTPS endpoints.
From a threat modeling perspective, this vulnerability aligns closely with CWE-918, which defines Server-Side Request Forgery as a weakness where a web server retrieves a specified resource from a user-supplied URL without validating that request. The exploitation technique maps directly to MITRE ATT&CK tactic T1557, specifically the Adversary-in-the-Middle subcategory or Lateral Movement techniques depending on the internal network topology. Attackers can leverage this SSRF vector to perform port scanning of internal hosts by observing response times and error messages, a technique often associated with reconnaissance activities within an enterprise environment. Additionally, the ability to reach cloud metadata endpoints poses a severe risk for credential theft in modern cloud-native deployments where instance metadata services are commonly used to retrieve temporary security credentials.
The consequences of successful exploitation can range from internal network mapping and service enumeration to more severe outcomes such as accessing sensitive configuration files stored on local servers or stealing authentication tokens from cloud provider metadata APIs. In environments utilizing microservices architectures, this vulnerability could potentially be chained with other flaws to achieve remote code execution if the SSRF target is a vulnerable administrative interface that allows command injection based on request parameters. The lack of TLS verification further complicates mitigation efforts because standard network controls like firewalls may not inspect encrypted traffic effectively unless deep packet inspection capabilities are deployed and configured, which is often resource-intensive and complex to manage at scale.
To mitigate this vulnerability, immediate remediation should focus on implementing strict allow-listing for the Fetcher.build_request function. Developers must validate that all user-supplied URLs resolve only to expected internal IP ranges or specific trusted domains, rejecting any requests targeting private IP addresses such as 10.x.x.x, 172.16-31.x.x, and 192.168.x.x, as well as loopback addresses like 127.0.0.1. It is also critical to enforce strict URL scheme validation, permitting only http or https protocols while blocking file, ftp, gopher, or other potentially dangerous schemes that could lead to local file inclusion attacks. Additionally, the validate_cert parameter should be set to True in production environments to ensure that TLS connections are properly authenticated and encrypted according to industry standards.
Long-term architectural improvements should include implementing a dedicated proxy layer for outbound requests from backend services. This proxy can enforce security policies centrally, logging all outgoing traffic for anomaly detection and ensuring that no direct network access is granted to internal resources without proper authorization checks. Network segmentation strategies should also be reviewed to ensure that the QD server resides in a DMZ or isolated subnet with restricted egress rules, limiting its ability to communicate directly with sensitive backend databases or management interfaces. Regular security audits and static code analysis tools configured to detect SSRF patterns can help prevent similar vulnerabilities from being introduced during future development cycles.