CVE-2026-120204 in DeepInfer
Summary
by MITRE • 10/31/2026
DeepInfer through 0.1.0 contains a path traversal vulnerability in the unauthenticated /profile endpoint that allows remote attackers to create arbitrary directories via the output_dir parameter. Attackers, including cross-site GET requests from an operator's browser, can write chrome trace files to exhaust disk or inodes and use error messages as a filesystem oracle.
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Analysis
by VulDB Data Team • 10/31/2026
The vulnerability identified within DeepInfer versions up to 0.1.0 represents a critical path traversal flaw located specifically in the unauthenticated /profile endpoint of the application. This security defect arises from insufficient validation of user-supplied input, particularly through the output_dir parameter which is intended to specify the destination for generated trace files. Because this endpoint does not require authentication, any remote attacker can interact with it directly without needing valid credentials or session tokens. The core technical failure lies in the application's handling of directory paths provided by the client; instead of sanitizing or restricting the input to a predefined safe base directory, the software accepts arbitrary path components that allow navigation outside the intended scope. This lack of strict canonicalization enables an attacker to manipulate the file system structure by injecting sequence characters such as dot-dot-slash sequences into the output_dir parameter.
From an operational perspective, this vulnerability facilitates two distinct and severe attack vectors against the target infrastructure. The first vector involves resource exhaustion through disk space or inode depletion. By repeatedly issuing requests with varying path structures that resolve to valid but non-existent directories within a writable location, attackers can force the application to create numerous empty folders. This activity consumes available storage capacity and file system inodes, potentially leading to a denial of service condition where legitimate users are unable to write new files or where the entire server becomes unstable due to resource constraints. The second vector is more insidious and involves using error messages as a filesystem oracle. When the application attempts to create directories that already exist or encounter permission errors during path traversal attempts, it often returns specific HTTP status codes or detailed error responses indicating whether the directory creation succeeded or failed based on existence checks. Attackers can leverage these differential responses to map out the underlying file system structure, identifying valid paths and sensitive locations even without direct read access to those files.
This type of vulnerability is formally classified under CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which highlights the failure to restrict path traversal sequences in user input. Furthermore, the exploitation technique aligns with ATT&CK tactic TA0043: Discovery and specifically sub-technique T1589.001: Gather Victim Identity Information - Credentials from Web Browser or similar reconnaissance methods where error-based enumeration is used to gather information about the target environment. The ability to use error messages as an oracle transforms a simple input validation flaw into a powerful reconnaissance tool, allowing attackers to probe for sensitive directories such as configuration files, database storage locations, or other application-specific paths that may contain further exploitable data.
Mitigation strategies must focus on implementing strict allow-listing for directory inputs rather than relying on block lists of malicious characters which can often be bypassed through encoding variations or alternative path representations. The output_dir parameter should be validated to ensure it resolves only within a designated, isolated temporary directory that has restricted permissions. Additionally, the application should normalize all file paths before processing them and verify that the final resolved path remains within the expected boundary using canonicalization techniques provided by standard libraries rather than string manipulation alone. Implementing rate limiting on the /profile endpoint can also help mitigate resource exhaustion attacks by preventing rapid-fire requests from a single source. Finally, ensuring that error messages returned to clients are generic and do not reveal internal file system details or existence checks is crucial for reducing the effectiveness of filesystem oracle techniques employed by attackers seeking to map out the server environment.