Summary
A path traversal vulnerability in the OneNote importer allows overwriting arbitrary files on disk.
Details
The OneNote converter does not sanitize the names of embedded files before writing them to disk. As a result, it's possible for an attacker to create a malicious .one file that includes file names containing ../../, that are then interpreted as part of the target path when extracting attachments from the .one file.
One affected location is embedded_file.rs, which generates a file name from a string previously parsed from the .one file,
https://github.com/laurent22/joplin/blob/af5108d70233b1db9410346958c1587cf7c1b16d/packages/onenote-converter/renderer/src/page/embedded_file.rs#L13-L16
Above, determine_filename passes through the provided file name.
Similar logic has been present since 4d7fa5972fe2986eae14cbf3a2801835cbe1384e (Joplin 3.2.2), when the OneNote importer was first introduced.
PoC
Screencast from 2025-11-20 13-50-21.webm
- Import poc_v2.zip.
- Open the application's profile directory, then open
log.txt.
- Observe that
log.txt has been overwritten non-log-file content (a WAV file).
Tested on Fedora Linux 43 with Joplin 3.4.12 (prod, linux) and Joplin 3.5.6 (dev, linux).
Note: The PoC ZIP file overwrites Joplin's log.txt. It is also possible to craft a file that overwrites more sensitive system files (e.g. .bashrc on Linux).
Impact
This is a path traversal vulnerability that impacts all versions of Joplin (<= v3.5.6) that include a OneNote importer. Importing a crafted OneNote export file allows an attacker to overwrite arbitrary files, potentially leading to remote code execution.
Patched in
References
msiemens Remediation developer
Summary
A path traversal vulnerability in the OneNote importer allows overwriting arbitrary files on disk.
Details
The OneNote converter does not sanitize the names of embedded files before writing them to disk. As a result, it's possible for an attacker to create a malicious
.onefile that includes file names containing../../, that are then interpreted as part of the target path when extracting attachments from the.onefile.One affected location is
embedded_file.rs, which generates a file name from a string previously parsed from the.onefile,https://github.com/laurent22/joplin/blob/af5108d70233b1db9410346958c1587cf7c1b16d/packages/onenote-converter/renderer/src/page/embedded_file.rs#L13-L16
Above,
determine_filenamepasses through the provided file name.Similar logic has been present since 4d7fa5972fe2986eae14cbf3a2801835cbe1384e (Joplin 3.2.2), when the OneNote importer was first introduced.
PoC
Screencast from 2025-11-20 13-50-21.webm
log.txt.log.txthas been overwritten non-log-file content (a WAV file).Tested on Fedora Linux 43 with Joplin 3.4.12 (prod, linux) and Joplin 3.5.6 (dev, linux).
Note: The PoC ZIP file overwrites Joplin's
log.txt. It is also possible to craft a file that overwrites more sensitive system files (e.g..bashrcon Linux).Impact
This is a path traversal vulnerability that impacts all versions of Joplin (<= v3.5.6) that include a OneNote importer. Importing a crafted OneNote export file allows an attacker to overwrite arbitrary files, potentially leading to remote code execution.
Patched in
References