Description

A security flaw has been discovered in Handwriting-OCR handwriting-ocr-mcp-server 0.1.0. Affected by this vulnerability is the function fs.readFileSync of the file src/index.ts of the component upload_document. Performing a manipulation of the argument File results in path traversal. Attacking locally is a requirement. The project was informed of the problem early through an issue report but has not responded yet.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.3",
  "pubDate": "2026-08-09T23:16:36.110Z",
  "pubdate": "2026-08-09T23:16:36.110Z",
  "executiveSummary": "A path traversal vulnerability exists in Handwriting-OCR handwriting-ocr-mcp-server version 0.1.0, specifically within the upload_document component inside the src/index.ts file. The flaw stems from insecure handling of input parameters passed to the fs.readFileSync function. An attacker capable of executing local operations can manipulate the File argument to traverse the file system and access arbitrary files outside the intended directory. This exposes sensitive local system files to unauthorized reading, compromising the confidentiality of the host environment. Exploitation requires local access to the system executing the affected component, and the project has not yet responded to early issue reports disclosing this vulnerability.",
  "technicalDetails": "The vulnerability is rooted in the src/index.ts file of the upload_document component within the Handwriting-OCR handwriting-ocr-mcp-server 0.1.0 package. Specifically, the implementation utilizes the Node.js core function fs.readFileSync to process files based on user-supplied input without adequate sanitization or validation.\nThe root cause of the flaw is the direct concatenation or utilization of the File argument in file system operations without enforcing path confinement or canonicalization checks (such as path.resolve combined with a safe base directory check). Consequently, an attacker can supply directory traversal sequences, such as dot-dot-slash (../) patterns, within the File parameter.\nThe attack flow proceeds as follows: First, the local attacker interacts with the upload_document component. Second, the attacker supplies a maliciously crafted payload within the File argument containing traversal sequences designed to navigate upward from the intended working directory to sensitive locations on the underlying host file system. Third, the application passes this unsanitized input directly into the fs.readFileSync function. Fourth, Node.js resolves the path and reads the targeted arbitrary file from the disk. Finally, the contents of the sensitive file are processed or returned by the component, resulting in unauthorized information disclosure.\nPrerequisites for exploitation include local access to the environment where the server component is running. The vulnerability does not require network exposure or authentication mechanisms if local execution bounds are met. Post-exploitation impact is characterized by the unauthorized disclosure of sensitive local files readable by the process execution context, potentially leading to the leakage of system configurations, credentials, or source code."
}