CVE-2026-80104 in DB-GPT
Summary
by MITRE • 08/26/2026
DB-GPT builds the destination path for an uploaded skill from the multipart filename without constraining it to the upload directory. skill_upload in packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py takes file.filename as given and writes the request body to upload_dir / filename. A path composed with that operator discards the left operand when the right one is absolute and follows parent references otherwise, so a filename such as ../../../tmp/x or /tmp/x resolves outside the intended directory; nothing canonicalises the result, checks that it remains under the upload root, or prevents a .py suffix. The route's only dependency is get_user_from_headers in dbgpt_serve/utils/auth.py, which returns a request carrying the admin role whether or not a user_id header is supplied, so the endpoint is reachable without credentials. A remote attacker holding no account can therefore write attacker-controlled bytes to any path the server process can write, place a new Python module inside the application package or replace one the application already imports, and obtain code execution in the server process when that module is next imported.
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in DB-GPT represents a critical combination of insecure file handling and authentication bypass mechanisms within its agentic data API. The core technical flaw resides in the skill_upload endpoint located at packages/dbgpt-app/src/dbgpt_app/openapi/api_v1/agentic_data_api.py, which constructs the destination path for uploaded skills by directly concatenating the upload directory with the filename provided in the multipart request without any sanitization or validation. This implementation fails to enforce strict constraints on the file path, allowing an attacker to manipulate the filename parameter to traverse directories outside of the intended upload root. Specifically, because Python's os.path.join operator discards the left operand when the right operand is absolute and resolves parent directory references such as ../ without canonicalizing the result, filenames like ../../../tmp/x or /tmp/x successfully escape the designated storage area. The absence of any mechanism to verify that the resolved path remains within the upload root directory creates a classic Path Traversal vulnerability, classified under CWE-22 in industry standards.
Compounding this file system issue is a severe authentication bypass flaw inherent in the endpoint's access control logic. The route relies exclusively on the get_user_from_headers utility function from dbgpt_serve/utils/auth.py to determine user privileges. This function exhibits flawed logic by returning a request object with admin role permissions regardless of whether a valid user_id header is present in the HTTP request. Consequently, the skill_upload endpoint is effectively public and reachable without any form of authentication or authorization credentials. This lack of access control allows unauthenticated remote attackers to interact directly with the file upload functionality, removing the primary barrier that would typically prevent unauthorized users from uploading arbitrary files to the server.
The operational impact of this vulnerability is severe, leading to Remote Code Execution on the target system. A remote attacker holding no account can exploit these flaws to write attacker-controlled bytes to any path within the filesystem where the DB-GPT server process has write permissions. By carefully crafting a filename that escapes the upload directory and appending a .py suffix, an attacker can place a malicious Python module inside the application package or overwrite an existing module that is imported by the application. When the server subsequently imports this compromised module during its normal operation, it executes the arbitrary code contained within, granting the attacker full control over the server process with the privileges of the user running the DB-GPT service. This scenario aligns with CWE-94 for Improper Control of Generation of Code and CWE-78 for OS Command Injection if shell commands are executed via the imported module.
From a threat modeling perspective, this vulnerability facilitates initial access through unauthenticated file upload, which can be mapped to MITRE ATT&CK technique T1505.003 (Web Shell: Web Shell). The attacker leverages the path traversal to place their payload in an accessible location and then relies on the application's import mechanisms for execution, a pattern consistent with persistence or privilege escalation tactics depending on the specific module targeted. To mitigate this risk, immediate remediation is required to enforce strict input validation on all file upload parameters. Developers must implement canonicalization of file paths before writing them to disk and verify that the final resolved path resides strictly within the allowed upload directory using methods such as os.path.realpath comparison against a whitelisted base directory. Furthermore, authentication checks must be corrected to ensure that administrative privileges are only granted when valid credentials or tokens are explicitly provided by an authenticated user, thereby closing the access control bypass identified in the auth utility function.