CVE-2026-49453: Joplin: Path traversal in resource sync — silent arbitrary file write outside the resource directory

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-21 · updated 2026-09-23
Weakness: CWE-20

Description

Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.6.15 and 3.7.2, Joplin accepts synchronized resource metadata whose id or file_extension contains parent-directory or path-separator characters. BaseItem.unserialize() stores the unvalidated fields, resourceFilename() concatenates them into a destination path, and ResourceFetcher writes the attacker-controlled resource blob outside the resource directory during background synchronization. An attacker with write access to a configured sync target or shared notebook can create or overwrite files at an attacker-chosen existing path without user interaction. This issue is fixed in versions 3.6.15 and 3.7.2.

Affected products

laurent22 joplin: before 3.6.15; from 3.7.0, < 3.7.2

References

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