CVE-2026-105783: Joplin Web Clipper pairing allows cross-origin theft of a permanent API token
Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.13, when Joplin Desktop is running with the opt-in Web Clipper server enabled, the server in packages/lib/ClipperServer.ts sends Access-Control-Allow-Origin: and allows an arbitrary website to call POST /auth and GET /auth/check because the pairing endpoints do not reject HTTP or HTTPS origins. The desktop confirmation dialog does not identify the requesting origin, so a victim who approves the generic prompt authorizes the attacking page, which then receives the permanent API token. The token provides ongoing read and write access to notes, folders, tags, resources, and master keys. This issue is fixed in version 3.7.13.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Joplin Desktopto a version that resolves this vulnerability.Fixed in 3.7.13
Event History
Frequently Asked Questions
Who is exposed to this issue?
Joplin Desktop users running a version earlier than 3.7.13 are exposed only if they have enabled the opt-in Web Clipper server. Exploitation also requires the user to approve the desktop pairing confirmation prompted by an attacker-controlled website.
What access does an attacker gain after successful exploitation?
The attacker receives a permanent API token. That token provides ongoing read and write access to notes, folders, tags, resources, and master keys.
How can this be remediated?
Update Joplin Desktop to version 3.7.13, which fixes the issue. Until updating, disable the Web Clipper server if it is not required and do not approve generic pairing prompts from the desktop application.