GHSA-gcmj-c9gg-9vh6 @joplin/onenote-converter: Path traversal in OneNote importer allows overwriting arbitrary files

• npm @joplin/onenote-converter: < 3.5.7 → fixed in 3.5.7

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 1. Import poc_v2.zip. 2. Open the application's profile directory, then open `log.txt`. 3. 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 • Joplin: https://github.com/laurent22/joplin/commit/791668455e1aae50501ff57ea4783b3fba9d377c • one2html: https://github.com/msiemens/one2html/commit/948d65cdca5bb35d776b8b235ec05ff15249fd41