Description

Budibase versions before 3.45.0 fail to disable external JSON reference resolution in the OpenAPI/Swagger import validator, allowing authenticated builders to read arbitrary local files. Attackers with builder access can embed file:// references in OpenAPI specifications submitted to the import endpoint to exfiltrate sensitive files including environment variables containing JWT secrets, API keys, and database credentials.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.1",
  "pubDate": "2026-09-26T14:16:52.150Z",
  "pubdate": "2026-09-26T14:16:52.150Z",
  "executiveSummary": "Budibase versions prior to 3.45.0 are susceptible to an Arbitrary File Disclosure vulnerability stemming from insecure handling of external references in OpenAPI/Swagger import functionality.\nThis vulnerability is classified as an XML External Entity (XXE)-style flaw within the JSON parsing logic, where the validator fails to disable external reference resolution during the processing of imported OpenAPI specifications.\nThe flaw allows authenticated users with 'builder' privileges to conduct server-side resource exfiltration by crafting malicious OpenAPI files containing file:// protocol references.\nSuccessful exploitation enables an attacker to read arbitrary local files residing on the host filesystem, potentially leading to the unauthorized disclosure of sensitive configuration data, including environment variables, JWT secrets, database connection strings, and third-party API keys.\nThis vulnerability poses a significant risk to the confidentiality and integrity of the application environment, as exposure of these credentials can facilitate further lateral movement or privilege escalation within the infrastructure.\nThe attack is limited to authenticated actors with builder-level access, meaning an attacker must already possess valid platform credentials to initiate the import process.",
  "technicalDetails": "The root cause of this vulnerability lies in the improper configuration of the JSON/YAML parser utilized by the Budibase OpenAPI/Swagger import validator. Specifically, the underlying library responsible for resolving references ($ref) within OpenAPI specifications does not explicitly disable the resolution of external schemas and local filesystem paths.\nWhen a user imports an OpenAPI specification through the Budibase interface, the validator processes the document to generate the corresponding schema. If the parser is configured to follow references without restriction, an attacker can embed a 'file://' URI within the $ref field of the OpenAPI document.\nThe exploitation flow begins with the attacker crafting a malicious JSON or YAML OpenAPI specification. Instead of pointing to a remote URL or a standard object, the $ref field is set to a path on the local filesystem (e.g., 'file:///etc/passwd' or 'file:///app/.env').\nUpon submission to the import endpoint, the Budibase backend attempts to resolve these references during the parsing phase. Because the library fails to validate or sanitize the URI scheme, the application engine executes the read request for the specified path.\nThe sensitive content retrieved from the target file is then reflected back to the attacker, often through the application's UI or error response messaging, or by processing the file content as part of the imported schema metadata.\nThis mechanism allows for the retrieval of highly sensitive system files. In a containerized environment, an attacker may exfiltrate the '.env' file, which frequently contains static secrets, encryption keys for session management (JWT signing keys), and credentials for external databases or cloud storage services.\nBecause the vulnerability exists in the validator component, the impact is severe; it circumvents standard access controls by leveraging the server's own filesystem permissions to read files that the service account process has access to.\nThe vulnerability is present in all Budibase versions before 3.45.0. Authentication is a prerequisite, as the import functionality is restricted to authorized builder-level accounts. No specialized network exposure is required beyond access to the Budibase management interface, making this a high-impact risk for multi-tenant or collaborative development environments where untrusted users may be granted builder access."
}