CVE-2026-46671
Received Received - Intake

Path Traversal in Rust OneNote File Parser

Publication date: 2026-07-20

Last updated on: 2026-07-20

Assigner: GitHub, Inc.

Description
Rust OneNote File Parser is a parser for Microsoft OneNote files implemented in Rust. Prior to version 1.1.1, a maliciously crafted `.onetoc2` table-of-contents file can cause `Parser::parse_notebook` to open arbitrary files on the host filesystem outside the notebook's directory. The parser reads entry names listed inside the `.onetoc2` and joins them against the notebook's base directory without validating that they are relative paths confined to that directory. The parser will bail out when the target file fails to parse as a OneNote section, so direct content exfiltration through the parser's return value is not practical, though file-existence probing and denial-of-service via large or special files remain possible. Anyone using `onenote_parser` to parse .onetoc2 files received from untrusted sources is affected. Users who only ever parse their own notebooks are not at meaningful risk. The issue is fixed in onenote_parser 1.1.1. The fix rejects absolute paths, parent-directory components, and other invalid path characters in entry names, and additionally canonicalises the resolved path to confirm it stays inside the notebook's base directory. For users who cannot upgrade to 1.1.1, only call `Parser::parse_notebook` on `.onetoc2` files from trusted sources. Alternatively, use `Parser::parse_section` / `Parser::parse_section_buffer` on individual .one files, which do not perform the directory walk.

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Meta Information

Published
2026-07-20
Last Modified
2026-07-20
Generated
2026-07-21
AI Q&A
2026-07-20
EPSS Evaluated
N/A
NVD
CVE-2026-46671
EUVD
EUVD-2026-45987

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
msiemens onenote_parser 1.1.1

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

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Executive Summary

This vulnerability is a path traversal issue in the Rust OneNote File Parser library. It affects versions prior to 1.1.1 and allows a maliciously crafted .onetoc2 file to cause the parser to access files outside the intended notebook directory. The parser reads entry names from the .onetoc2 file and joins them with the notebook's base directory without validating that the paths are relative and confined to that directory.

Detection Guidance

Detecting this vulnerability requires checking if you are using a vulnerable version of the onenote_parser library (prior to 1.1.1). Inspect your project's dependency files (e.g., Cargo.toml for Rust) to verify the version. Additionally, monitor for unusual file access patterns or errors when parsing .onetoc2 files.

Impact Analysis

The impact includes file-existence probing, where attackers can check if specific files exist on your system. It may also cause denial-of-service by targeting large or specially crafted files. Direct content exfiltration is unlikely due to parsing failures, but the vulnerability still poses a risk if you parse .onetoc2 files from untrusted sources.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by enabling unauthorized file access. A path traversal flaw allows attackers to probe for or access files outside the intended directory, which may include sensitive data like personal or health information. Unauthorized access to such data violates GDPR's data protection principles and HIPAA's confidentiality requirements, potentially leading to regulatory penalties.

Mitigation Strategies

Upgrade to onenote_parser version 1.1.1 or later. If upgrading is not possible, avoid parsing .onetoc2 files from untrusted sources. Use Parser::parse_section or Parser::parse_section_buffer for individual .one files instead. Ensure your system restricts file access permissions to minimize potential impact.

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