CVE-2026-59815

Joplin Server prior to 3.7.7 contains a stored XSS vulnerability in the GET /shares/:id?resource_id= route, which serves a resource with the attacker-controlled mime value and omits Content-Disposition when the resource title is empty. A low-privileged user can publish an empty-title image/svg+xml attachment whose script executes when a victim opens the public share. By default, user content shares the Joplin Server application origin, allowing the script to access same-origin data and, when the victim is authenticated, perform actions with the victim's session, including reading administrative data and anti-CSRF tokens.

Joplin Server prior to 3.7.2 contains a vulnerability in UserModel.ssoLogin() that returns an existing account matched by an IdP-asserted email without checking the account's is_external flag. In deployments using mixed local and SAML authentication, an attacker whose IdP session can assert a local user's email can pass POST /api/saml, receive a session for that local account, and access or modify the victim's notes, files, and settings without knowing the local password.

Joplin Server before version 3.7.7 with TRANSCRIBE_ENABLED=true has a vulnerability in the GET/POST /api/transcribe/:id routes where the decoded id is passed directly to transcription backend URLs. An authenticated user can use URL-encoded slash and parent-directory segments to escape the intended /transcribe/ prefix and proxy requests to other internal endpoints, potentially exposing administrative, health, or configuration data. This issue is fixed in version 3.7.7.

Joplin Server before version 3.7.2 has a vulnerability in the GET /items/:id/content route that loads item content from an attacker-supplied internal server ID without checking whether the signed-in user owns or can access that item. Any authenticated user who obtains or guesses another user's item ID can read the corresponding note or item content when end-to-end encryption does not protect it. This issue is fixed in version 3.7.2.

Joplin is an open source note-taking and to-do application that organises notes and lists into notebooks. Prior to 3.7.2, Joplin Server's GET /api/login_with_code/:id endpoint accepts a nine-digit SSO authentication code with a ten-minute lifetime without applying limiterLoginBruteForce. An unauthenticated attacker who targets a user during an active SSO login can make unlimited guesses, and a correct code returns a full session token that permits access to and modification of the user's notes, notebooks, and account settings.