CVE-2026-80050 in Admin
Summary
by MITRE • 08/25/2026
ContiNew Admin fails to apply file-upload permission checks or file-type allowlist validation to multipart upload endpoints, allowing authenticated users to store files with arbitrary extensions. Attackers can initialize chunked uploads, send file parts, and complete uploads to leave arbitrary files in the storage backend accessible via web server URLs.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability identified in ContiNew Admin represents a critical failure in input validation mechanisms specifically within multipart upload endpoints. This flaw stems from an absence of rigorous permission checks and a missing allowlist for file types, which are fundamental security controls designed to restrict user actions to authorized operations and safe data formats respectively. In standard web application architecture, file upload functionality is often one of the most complex components due to its interaction with both the HTTP protocol and the underlying operating system's file storage mechanisms. When these endpoints fail to validate that an authenticated user has explicit permission to perform a specific type of write operation, or when they neglect to verify that the uploaded content matches expected MIME types or extensions, the application effectively trusts client-supplied metadata without verification. This lack of validation allows any authenticated actor to bypass intended restrictions and interact with the storage backend in unintended ways.
From a technical perspective, this vulnerability enables attackers to exploit the multipart upload process by initializing chunked uploads, sending file parts containing malicious payloads such as web shells or scripts, and completing the upload sequence. Because there is no server-side enforcement of an allowlist for permitted extensions like images or documents, the system accepts files with arbitrary extensions including executable formats or script languages supported by the web server environment. Once these files are stored in the backend storage, they become accessible via standard web server URLs. This transforms a simple file upload feature into a remote code execution vector if the uploaded content can be interpreted and executed by the hosting infrastructure. The ability to store arbitrary files directly impacts the integrity of the application's data layer and provides a persistent foothold for further exploitation within the network environment.
The operational impact of this vulnerability is severe, as it compromises both confidentiality and availability in addition to integrity. An attacker who successfully exploits this flaw can deploy web shells that allow interactive command execution on the server hosting ContiNew Admin. This leads to full system compromise where sensitive administrative data, user credentials, or proprietary information stored within the application's scope can be exfiltrated. Furthermore, the presence of unauthorized files in accessible directories may facilitate lateral movement if the storage backend is shared with other services or if the web server configuration permits script execution from those locations. The vulnerability aligns closely with CWE-434 which describes the unrestricted upload of file types that could lead to remote code execution, and it also relates to CWE-285 regarding improper authorization checks during resource access. In terms of offensive security frameworks such as MITRE ATT&CK this behavior corresponds to techniques involving web shell deployment and unauthorized data storage often categorized under initial access or persistence tactics depending on the attacker's subsequent actions.
Mitigation strategies must focus on implementing defense-in-depth controls at both the application logic level and the infrastructure configuration layer. The primary remediation involves enforcing strict server-side validation of file types using a denylist for dangerous extensions combined with an allowlist for safe ones, ensuring that only expected MIME types are accepted regardless of client-supplied headers. Additionally, developers should implement robust permission checks to verify that authenticated users have explicit authorization to upload files before processing the multipart request. It is also critical to store uploaded files outside of web-accessible directories or in isolated storage buckets with restricted access policies so that even if malicious content is stored it cannot be directly executed by a web server. Renaming uploaded files upon ingestion and scanning them for malware signatures further reduces risk. Regular security audits focusing on file handling routines and continuous monitoring for anomalous upload patterns are essential to maintain the integrity of the application against such exploitation attempts.