CVE-2026-22810: Joplin: Path traversal in OneNote importer allows overwriting arbitrary files
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 embeddedfile.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/embeddedfile.rs#L13-L16
Above, determinefilename 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 pocv2.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
Other sources
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Versions prior to 3.5.7 contain a path traversal vulnerability in the importer which allows overwriting arbitrary files on disk. 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. This issue has been patched in version 3.5.7.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/@joplin/onenote-converterto a version that resolves this vulnerability.Fixed in 3.5.7 - Upgrade
Upgrade
Joplin (OneNote importer)to a version that resolves this vulnerability.Fixed in 3.5.7 - Compensating control
If you cannot upgrade immediately, do not import untrusted OneNote export (.one) files into Joplin because the OneNote converter does not sanitize embedded file names before writing them to disk (path traversal via names containing "../../").
- Operational
Check the Joplin profile directory for unexpected modification of log.txt (e.g., log.txt overwritten with non-log content) after any exposure to a crafted OneNote export, and remediate affected files accordingly.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-22810?
CVE-2026-22810 is considered a high severity vulnerability due to its ability to overwrite arbitrary files on disk.
How do I fix CVE-2026-22810?
To fix CVE-2026-22810, update the OneNote converter to version 3.5.7 or later.
What software is affected by CVE-2026-22810?
CVE-2026-22810 affects the OneNote importer part of the @joplin/onenote-converter package.
What type of vulnerability is CVE-2026-22810?
CVE-2026-22810 is a path traversal vulnerability that allows for file overwriting.
How can CVE-2026-22810 be exploited?
An attacker can exploit CVE-2026-22810 by crafting a malicious .one file that contains unsanitized embedded file names.